3H1P: Do I ever succumb to superstition?

Welcome to my first entry in Ziztur’s “3H1P” project. To quote her own description,

3H1P is a blogging project wherein three heathens (Ziztur, Flimsy and Petter) and one pastor (Keith) answer questions posed by readers of the blog and discuss various issues related to religion, philosophy, science, etc. If you have a question that you'd like to see answered by 3H1P, ask it in the comment box. We promise we'll probably get to it.

Some time back, EdW wrote:

I would love to hear about whether The 3 Heathens (which sounds like the best/worst Disney feature ever) find themselves succumbing to superstition in their lives. Personally, I have an assortment of "lucky" objects that I carry -- and I love to make bargains with the Universe, or my car. "I promise I'll get you premium gas next time if you just don't die on the way to the airport".

I guess the question would apply to P.Keith as well -- do you ever find yourself doing things that you consider superstitious and silly?

I think it's important on both sides to acknowledge that we all are perfectly capable of believing absurd things, and sometimes that's okay. My lucky objects are great conversation starters.

-EdW

I also seem to recall a question in some blog comment—though as I cannot find it, it may be that I misremember—asking whether we heathens ever doubt the correctness of our atheism. Whether the question was asked or not, I think it’s a good question that works well as a subquestion to the above. As is my wont, I will take these talking points and, rather than provide a succinct answer, extrapolate and wax philosophical about it.

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I can’t think of instances when I succumb to superstition, for the simple reason that if I am aware of it, I refuse to allow myself to do so. That does not, of course, mean that I don’t succumb, only that if I do, I do so when I’m unaware of the fact…and I expect that this does happen. After all, we are all human; we are all subject to the same cognitive biases, type I (false positive) errors, pareidolia, rampant teleology, confusing correlation with causation, and all the rest. On top of that, in our daily lives we have to deal with the cognitive limitations of being individual people and dealing with sample-of-one events rather than having the leisure to evaluate everything as a proper scientific experiment.

On top of this, there is the interesting idea I have heard bandied about that truly understanding an idea requires a thought process virtually identical to actually believing it—temporarily suspending disbelief. I do not know whether this is literally true or not, and for my purposes this is irrelevant. In my own, subjective experience, it certainly appears that truly understanding an idea requires adopting a point of view from which the positive arguments make sense. It is true that when I read some of the more well-written arguments for some fantastic thing or other, be it Christianity or naturopathy or ESP, there is a part of my brain that goes “Huh” and has to be reined in once I sit back and apply critical thinking.

(On an aside, this means that there are plenty of things I simply cannot understand, but dismiss nonetheless. I do not think this unjustified. If a belief clearly leads to particular predictions that do not hold, or relies on flawed assumptions, I can safely dismiss the whole edifice even if I do not know what it is like to mentally inhabit it. I cannot imagine what it is like to live in a universe where 2+2=5, but I don’t need to; I know it is untrue nonetheless.)

So on any given day, I—hard-nosed skeptic extraordinaire—may very briefly belief in Christianity, Islam, telepathy, and who knows what. I may wish I didn’t, but such is the case: Especially with Christianity; after all I grew up Christian, if not very hardcore, and I was at least ten years old by the time I realised that the painful “crisis of faith” I had suffered, complete with prayers for “a sign”, was really the anguish of cognitive dissonance as I strove to believe in something unbelievable.

Perhaps you, gentle reader, have also experienced the phenomenon of agreeing with a writer or a speaker so long as you are reading, or listening, to his or her words—only to emerge from the spell and start questioning? My tendency to do this is probably why I prefer reading to listening when it comes to (purported) fact, as I find it easier to pause and critically analyse something when I’m reading it than if I’m swept along by the pace of the spoken word (this is why I read blogs but do not listen to podcasts).

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Ironically, one of the best responses to this temporary vacillating comes from C.S. Lewis and his Mere Christianity—I generally disliked it, but I found this part inspiring:

Roughly speaking, the word Faith seems to be used by Christians in two senses or on two levels, and I will take them in turn. In the first sense it means simply Belief—accepting or regarding as true the doctrines of Christianity. That is fairly simple. But what does puzzle people-at least it used to puzzle me—is the fact that Christians regard faith in this sense as a virtue. I used to ask how on earth it can be a virtue—what is there moral or immoral about believing or not believing a set of statements? Obviously, I used to say, a sane man accepts or rejects any statement, not because he wants to or does not want to, but because the evidence seems to him good or bad. If he were mistaken about the goodness or badness of the evidence that would not mean he was a bad man, but only that he was not very clever. And if he thought the evidence bad but tried to force himself to believe in spite of it, that would be merely stupid.

Well, I think I still take that view. But what I did not see then—and a good many people do not see still—was this. I was assuming that if the human mind once accepts a thing as true it will automatically go on regarding it as true, until some real reason for reconsidering it turns up. In fact, I was assuming that the human mind is completely ruled by reason. But that is not so. For example, my reason is perfectly convinced by good evidence that anaesthetics do not smother me and that properly trained surgeons do not start operating until I am unconscious. But that does not alter the fact that when they have me down on the table and clap their horrible mask over my face, a mere childish panic begins inside me. I start thinking I am going to choke, and I am afraid they will start cutting me up before I am properly under. In other words, I lose my faith in anaesthetics. It is not reason that is taking away my faith: on the contrary, my faith is based on reason. It is my imagination and emotions. The battle is between faith and reason on one side and emotion and imagination on the other.

In this sense—and only in this specific sense—it is with faith in my convictions of the rational approach to the universe that I meet these momentary weaknesses. Faith-1 is bad; faith-2 is a good thing, and we need it to counter the non-rational vacillations of our primate brains.

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To draw on a concrete example, I went for my flu shots back in the fall. (I was lucky enough to get both the seasonal and H1N1 shot, even though I did not qualify as a member of any of the H1N1 priority groups at the time: The clinic had prepared too many doses that morning, and the doctor offered them to non-qualifying patients rather than having to throw them out at the end of the day.) I read a lot about vaccination, and about anti-vaccination shenanigans. I am among those who regard vaccinations as the second greatest medical invention or discovery of all time (right behind the medical importance of hygiene). I consider the anti-vaccination movement dangerously misguided at best, and am happy to refer you here to ponder its consequences.

And yet, actually walking into the clinic to get those shots was not psychologically trivial. In part this is no doubt because I’m not a big fan of needles, but I also had a small encyclopedia of anti-vaccination claims floating in my mind, accompanied by fears ranging from the ludicrous—think squalene, aluminium adjuvants, antifreeze, mercury causing autism—to the disproportionate, such as the (in fact extremely minute) risk of Guillain-Barré syndrome, a very rare side effect of flu vaccination. I would be lying if I said that I went in without any hesitation.

But I know better than to just listen to my fears. I have faith-2 in the safety of vaccines, in the fact that while there are a few tiny risks, the odds that it will save my life from disease (and protect people around me whom I might otherwise infect) are vastly greater than those risks; and some of the risks aren’t real at all. So I went in, got my shots, took a low-key day of reading, coffee, and puttering around with my computer as I suffered the common side effect of mild ache and fever the next day, and went back to life as usual the day after that. (I did not contract Guillain-Barré syndrome, I did not become autistic, and in general suffered no side effects.)

This is not the only example I could give. I try to apply the same sort of critical thinking whenever I am faced with a choice and feel a gut instinct that does not seem well supported by evidence. It happens that my response to a difficult choice is to look up statistics and do my best to mathematically assess statistical probabilities rather than attempt to tackle emotionally laden issues head-on. (Did you know, for instance, that some 20% of the population carries HSV-2, the virus that causes ‘genital’ herpes, but 80% of them don’t know it? This means that about 17% of everyone who is not aware of carrying HSV-2 actually does, and if you have protected sex with a person of unknown HSV-2 status, you run—very approximately—a 0.42% annual risk of contracting the virus if you are male, twice that if female. HSV-2 is not tested for in standard STI screening panels.)

I’m told I’m uncommonly rational about such things—which I take as a great compliment, even if it’s a bit disturbing to think that most people do not try their best to rationally evaluate risks and probabilities. To me, it seems irresponsible not to try. Of course, I’m sure that I often fall short—but as I said in the beginning, I don’t allow myself to fall short when I’m aware of the problem.

The disturbing question is, how often do I face a hard choice and go with my gut reaction without first questioning it? I don’t know.

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My model for dealing with gut feelings is, of course, Carl Sagan. As he memorably recounted in The Demon-Haunted World,

I’m frequently asked, Do you believe there’s extraterrestrial intelligence? I give the standard arguments—there are a lot of places out there, the molecules of life are everywhere, I use the word billions, and so on. Then I say it would be asonishing to me if there weren’t extraterrestrial intelligence, but of course there is as yet no compelling evidence for it.

Often, I’m asked next, What do you really think?

I say, I just told you what I really think.

Yes, but what’s your gut feeling?

But I try not to think with my gut. If I’m serious about understanding the world, thiniing with anything besides my brain, tempting as that might be, is likely to get me into trouble. Really, it’s okay to reserve judgment until the evidence is in.

“The G-spot 'doesn't appear to exist', say researchers”

An article I recently read boldly claims that The G-spot 'doesn't appear to exist', say researchers. I read this with a sigh, as I know from experience how greatly distorted any research findings can get when they are published in mainstream media. Clearly, this was an instance of such distortion. I was curious to see what the actual study said, and went off to find it. You may read it here, if you are curious.

Sadly, it wasn’t very distorted after all.

In fact, the press release from the Department of Twin Research & Genetic Epidemiology was worse than the articles I had read. It presents the following conclusion from their study:

The complete absence of genetic contribution to the G-Spot, an allegedly highly sensitive area in the anterior wall of the vagina which when stimulated produces powerful orgasm, casts serious doubt on its existence, suggests a study by the Department of Twin Research to be published in the Journal of Sexual Medicine.

The investigators carried out this study by recruiting 1804 female volunteers from the TwinsUK registry aged 23-83 years. All completed questionnaires detailing their general sexual behavior and functioning, and a specific question on self-perception of the G- Spot. The researchers found no evidence for a genetic basis. This led to the conclusion that – given that all anatomical and physiological traits studied so far have been shown to be at least partially influenced by genes – the G-Spot does not exist and is more a fiction created by other factors e.g. an individual’s own sexual and relationship satisfaction or self-report is an inadequate way to assess the G-Spot and researchers should in future focus more on ultrasound studies.

The impression I took from the mainstream press articles, and which was reinforced by the institute’s press release, was that the existence of the G-spot was inferred to correspond to study participants’ reports of whether they had one. If this were so—if we could determine anatomy by poll—I expect I could find some people with more spleens than kidneys and more livers than lymph nodes.

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I took the trouble to read the actual paper (it’s fairly short and quite accessible). The reality turns out not to be quite so bad. The main point—well, let me make an aside here and say that I find it extremely odd that what seemed to be the main point emphasised in the paper was considerably de-emphasised in the press release and consequent mainstream articles, seriously reducing their credibility. Anyway, back to the point:

The main point of the paper is that if the G-spot exists, it is an anatomical structure; if it is an anatomical structure, it is presumably genetically inherited. Even if some women have it while some don’t, we expect to find a strong correlation in twins. Since heterozygotic twins share 50% of their genome, and monozygotic (‘identical’) twins share 100% of their genome, if it’s genetically heritable at all, we should see a correlation in twins, especially monozygotic ones: If one twin has it, the other should (more often than is the case with unrelated people); if one twin does not, the other shouldn’t. Because twins are typically raised in extremely similar environments, even environmental factors should be similar. In particular, monozygotic twins should be more similar to each other than heterozygotic twins for heritable (but not environmental) factors.

Well, this turned out not to be the case: Heterozygous twins report that they have G-spots about as often as do monozygous twins, and this is the real point of the paper. It’s not as spectacular as the mainstream news articles, but I’m surprised that they so failed to emphasise this in their own press release. Ah well, such is the hunt for fame, I suppose.

In the conclusion of the real, scientific paper, the authors are of course forced to admit that

A possible explanation for the lack of heritability may be that women differ in their ability to detect their own (true) G-spots.

They, of course, do not believe this to be the case. We may reasonably ask, why not? And how good is your evidence? My thoughts will be very tentative, because I’m not an expert in any related field; but we may at least reason about it.

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First, I will note that the study’s exclusion criteria were, at times, a bit puzzling.

Women who reported that they were homo- or bisexual were excluded from the study because of the common use of digital stimulation among these women, which may bias the results.

I daresay it may bias them! For example, if the G-spot exists, it’s a specific anatomical location inside the vagina. Because it is postulated to be a very specific location, it may be difficult to stimulate with the penis, which is after all not prehensile and may not be angled so as to optimally stimulate a specific location. This postulated spot could perhaps be more easily located and stimulated with the fingers. Therefore, if it does exist, and if we are restricted to self-reporting as evidence, I would expect to find much stronger evidence for this in a population with common use of digital stimulation. The people I would ask first are the people whose answers they discarded. I would be very curious to see how their data are affected if they include this population. What was their rationale for the exclusion criterion? Was it determined beforehand, or after the data were in? Would it contradict their conclusion? What if this population were considered exclusively?

This looks like a very serious weakness to me, as the exclusion criterion seems to be specifically geared towards reaching a particular conclusion. (I can’t think of anything much more damning I could possibly say about a study.) It’s not the only thing that makes me raise an eyebrow, though (but it is the strongest).

Another thing is that, well, some traits just aren’t very heritable. (This is why we measure heritability; if there weren’t variation in how strongly phenotypic traits are associated with genes, there’d be no need.) I suppose the authors may reasonably expect their readership to be familiar with not just the concept of heritability (as I am), but also what kind of numbers we should expect (as I am not). Is a “close to 0” heritability common, or unusual, or rare, or impossible in variable phenotypic traits? Still, it is possible that heritability of the G-spot—not necessarily its existence, but perhaps its precise location and orientation, or its sensitivity—is relatively low. Is the study still powered to detect it? How does this render it more vulnerable to other confounders?

There are various criticisms leveraged against twin studies in general. Twin studies are potentially wonderful tools because monozygotic twins offer unique opportunities to investigate heritability. (Personally, I think the most interesting ones are of that rarity of rarities, pairs of monozygotic twins raised apart; the surprising similarities they show in a very wide range of behavioural traits is strong evidence of genetic conditioning.) But they are not perfect.

And finally, I make the observation that the institute—the Department of Twin Research & Genetic Epidemiology—maintain a database of twins (an awful lot of them: Some 11,000 people). This is great; it enables them to efficiently perform twin studies. However, studying the same sample over and over again is problematic. If you look at the same N people, examining them for different properties over and over again, you’re bound to find an apparent correlation eventually. Think about it: If you pick 100 names at random from a phone book, you’ll expect about half of them to be male, half female; and about 8–15 of them to be left-handed…but if you examined them for blood pressure, and dietary habits, and sexual preferences, and number of children, and so on for any number of questions, it would be bizarre if they were an average sample in every respect. This is a problem with data mining. Clearly, the department’s database is pretty large, but then they’ve already published over 400 research papers. At what number of papers should we statistically expect to find spurious calculations?

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All in all, the study was a bit more sensible than mainstream media had me thinking at first, but as research papers go, I found it surprisingly unimpressive. In particular, the exclusion criterion that discarded answers from gay and bisexual women smells very fishy, and I wouldn’t be terribly surprised if it “biased” the results so far as to invalidate their conclusion.

In a general sense, I trust science—I trust the scientific method, and (to a lesser but considerable degree) I trust that scientific consensus will move toward the right answers: Science is often characterised as an asymptotic approach to the truth (we may never know it exactly, but we will get ever closer). However, when considering a single study, one should be cautious. Never trust what the mainstream press says about it at all, whether you like what it says or not—ordinary reporters lack scientific savvy, good science reporters are rare, and after the editors have their say, it’s often dubious whether the scientists behind a finding would agree with anything the press has to say about them except, perhaps, the scientists’ names.

And while the scientific method is excellent, and the scientific consensus is the best approach we have to knowledge, some studies just aren’t worth the paper of the webpages they’re published on. If you want to adjust your opinions according to a single study, read it. Read it critically.

Life does not begin at conception

One of the primary claims of the anti-abortion brigade is that “life begins at conception”, and because it is wrong to take a life, therefore it is wrong to abort a fetus (and perhaps wrong even to prevent a zygote from implanting by use of a UTI). However, this claim is not merely wrong, but ludicrously wrong.

Let me make an aside here. If you are of a religious bent, and if you believe in the existance of a soul, and if you believe that this soul is created, implanted, magicked into being, or otherwise attached to a developing human at some particular point in development, then of course that provides a logical point whereafter abortion may be seen as a crime against said soul. I think you are dead wrong about the existance of souls, but granted that premise, this objection to anti-abortionism does not apply to you. To you, all I have to say is this: Remember that your arguments are inherently non-secular and cannot carry force in a secular judicial system; and please remember that your arguments hold no force with those of us who are not religious.

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With that out of the way, let’s restate the obvoius: Life does not begin at conception. Conception, in us sexually reproducing animals, consists of the fusion of gametes—the sperm fertilises the ovum. But, and this should be painfully obvious to everyone, the gametes are alive. You are the product of a living spermatozoon and a living ovum. Fertilisation did not mark the creation of life, only the fusion of two living cells into a single living cell.

This fusion is certainly a defining moment in your life. Barring mutation so unlikely that I expect it can be discounted, and excepting rare conditions like chimerism and mosaicism, it is the last event that defines your genetic makeup, when the chromosomes you inherit from your parents merge. It is, in a very real sense, a defining moment. It is not, however, the defining moment, because there are many. Even after fusion, not every zygote goes on to successfully implant, and early pregnancies often terminate spontaneously. The biologist Lewis Wolpert famously said that “It is not birth, marriage, or death, but gastrulation which is truly the most important time in your life”.

But before conception, a startling number of things had to happen in order to make you who you are. Before the fertilisation event was to matter at all, the specifics of meiosis in the germ line of each of your parents played as big a role in determining your genetic specifics as did the fertilisation itself: Meiosis, the process where a germ line cell divides into (haploid) gametes with half the chromosomal complement of a normal cell, is when the genetic contribution of each parent is determined. And of course any number of things had to happen very specifically in order to make you who you are, on this basis: Your parents had to have sex at just the right time when the spermatozoon and ovum each carrying half of your genes were alive and active. If they’d waited until next month, things would have been different…

But this is only the beginning (or the end, depending on your view). Those haploid cells, after all, were alive, each of them a living cell from one of your parents, whence they were produced by meiosis from diploid germ line cells. Each of those cells was the unlikely product of very specific meiosis, reproductive timing, and fertilisation by the (most likely four) people who were their parents…and the same goes for all of their parents…and that lineage goes back, centuries, millennia, millions of years, hundreds of millions of years. You are the product of a lineage of living cells that stretches back to the very dawn of sexual reproduction. Looking back further, you’re still the product of living cells, though the processes are different and lateral gene transfer makes the family tree a bit harder to draw…but ultimately, you are the scion of a family of cells—living cell to living cell to living cell—reaching back some 3.6 billion years—3,600,000,000 years—at a ballpark estimate.

That is when life began, and that is, in a sense, when your life began, too: It started then, and it hasn’t died since. Every single intermediary between you and the first primordial, primitive, living cell that serves as ancestor to all life on earth was alive. It started then, and in a sense, you’re just a heavily modified offshoot—3,600,000,000 years down the living line.

I find this an awesome fact to contemplate.

What, then, is so magical about conception? Nothing, really. It’s a defining moment in making you who you are, but it’s really just one of billions upon billions of defining moments. Causing the death of a zygote does exactly as much in preventing a particular potential person from coming about as does causing the death of a spermatozoon (e.g. by masturbating, by ejaculating outside a woman, by using a condom, or by doing nothing and letting the spermatozoon die and get reabsorbed into the body); as does wasting the life of an ovum (by menstruating, in the luteal or ischemic phase). But removing the possibility of a specific human being is even more ubiquitous; after all, every human alive represents millions of potential people lost, as the ones produced by the spermatozoa who lost the race would undoubtedly have been different.

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My own opinions on abortion are not very well-defined. I am, of course, pro-choice, but since I’ve never been in a position where I’ve had to make a hard choice, I’ve never needed to figure out exactly what I think the hard lines are. What I do think, however, is that it is in no way wrong to destroy human tissue, while it is definitely wrong to destroy a moral human person.

The question, then, is what constitutes moral personhood. I will not pretend to have a clearcut answer. If I had to sit down and develop one, it would combine concepts like having thoughts, dreams, hopes, fears, and desires; taking part in emotional relationships (a reciprocal relationship); interacting (in some way) with people; acting as a moral agent, rather than merely being acted upon as a ‘moral object’.

It seems abundantly clear to me that no lump of human tissue can possibly meet my criteria unless it has a mind, which requires a working brain. After the brain works in some sense, I believe there is a window, a grey area, where I would in all likelihood agree that abortion may very well be morally acceptable—but this is beside the point I wish to make here, which is that until brain activity begins, I regard it as “no context”: Abortion prior to this is absolutely acceptable. (This may be around week 25 or so of a pregnancy; research shows that sustained EEG activity first appears in bursts around week 20, become sustained around week 22, and bilaterally synchronous around weeks 26–27.)

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Once the position is taken that an early abortion does not, in fact, destroy a moral person, we are back to the notion of destroying “potential” persons. The problem is that we destroy potential persons all the time, no matter what we do. If we have sex, we destroy lots of potential persons (since most of the potential ones will never be, even if we do have children); whenever we don’t have sex even though we could, we are passively murdering potential persons, because we aren’t making children at all.

Modern biotechnology allows us to stretch this argument to a reductio ad absurdum without leaving the realm of the possible. In recent experiments (documented in some very nice articles in Nature), scientists have induced pluripotency in mouse cells and produced viable mice (fully viable, as some of them went on to reproduce). While cloning humans is likely to be much more difficult than cloning mice even on purely technical considerations, and it may well be impossible right now, it seems obvious that the technology is if not in our grasp, then certainly close to it, to produce viable humans from induced pluripotent stem cells. Taking things just a bit further, it may become possible to extract genetic material and inject it into pluripotent cells and so produce clones from any cell with intact genetic material.

Once the technology exists for doing this, the loss of any viable genetic material is, in a sense, the destruction of a potential human life. Scratching your head, cutting your hair or your nails, losing scrapings of epithelial material from your mouth, bleeding…every such act will prevent humans from being who might otherwise have been.

Unless you are willing to condemn this as murder, then any argument that boils down to “You are destroying potential life!” loses all force.

Fallacies and lies in the gay marriage debate

Opponents of gay rights often object to gay marriage on the basis that it is “not traditional”—“traditional marriage”, they say, never included same-sex unions; therefore, to allow such would be to subvert what marriage is about.

Skipping quickly past the most obvious flaws in this argument—viz., first, that “traditional” and “non-traditional” do not necessarily correlate to “good” and “bad” at all; and second, that a non-traditional marriage is still a marriage—it is still a flimsy argument, for a series of reasons. Since I seem to repeat myself in comment threads, I will summarize my arguments here for future reference.

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The most oft-raised objection is that the tradition of marriage has changed over time, thus appeals to tradition are vague and empty. For instance, going back a few decades or centuries we will find changes in

• whether people were encouraged or even allowed to choose their own spouses
• whether marriages could be dissolved by divorce
• whether women held equal power (legally) with their husbands
• whether the spouses could have different ethnic, cultural, and/or religious backgrounds
• and so on and so forth.

Some people misunderstand this argument and object that “same-sex unions were never part of the tradition!”—which is true, but completely misses the point. The point is that the tradition has always been plastic and has evolved over the decades and centuries, and rules have been changed or dropped—generally, it seems, as a delayed reaction to humanistic improvements in our culture. It is certainly true that “the spouses must be of different sexes” has always been one of those rules, but if other rules can be dropped, why can’t that one?

You may be reaching for the reply button to tell me that, wait!, there is a good reason!—that same-sex unions cannot “naturally” produce children, for instance. However, this is a red herring. If you must resort to any such argument, you are no longer arguing that gay marriage is wrong because it is non-traditional, but rather that it is wrong and non-traditional. If you want “It’s not traditional!” to be a reason against gay marriage, then you must be consistent. However, virtually nobody actually argues in favour of other, discarded aspects of the tradition. Therefore, “It’s not traditional!” is not really a motivation at all, but a rhetorical argument disingenuously wielded for want of better arguments.

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While we are at it, let’s dismiss the motivation that same-sex marriages are invalid because they cannot result in children. First, this is simply untrue—lesbian couples can have children with the help of artificial insemination, or a male friend; gay male couples can have children with the aid of a surrogate mother; any gender configuration can raise children if they are adopted. Second, the people who argue that gay marriages should not be allowed because they do not result in children by “natural” means never seem to have the slightest urge to apply this criterion consistently, which would mean forbidding marriages

• where the woman is post-menopausal
• where the man is sterile or completely impotent
• where the woman is infertile
• where the man has had a vasectomy, or the woman a tubal ligation
• where the spouses are biologically capable of having children, but have no desire or intention to do so, and use contraceptives to ensure it will not happen.

If your criterion is that “marriage is for procreation”, then you should oppose these types of marriage every bit as firmly as you oppose same-sex marriage. If you don’t, then whatever your real reason is, it clearly isn’t the procreation angle.

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Finally, something that is often overlooked is that defenders of “traditional” marriage tend to speak as though there were only one tradition (their own, of course). But this is not so, and while we may live in a culture evolved from and dominated by Judeo-Christian tradition, it’s not the only one around. The tradition of male-male eros in ancient Greece is well-known; in modern times, it is fairly clear that so-called Boston marriages often (though far from always) were, in effect, lesbian partnerships.

Around the world, there have been many cultures and traditions that allow, encourage, or celebrate same-sex relationships. Anthropologists have found several dozen African populations with female-female marriages, as well as male-male unions; North American indigenous cultures have recognised various fluid gender identities; pre-modern China had several examples of same-sex marriages.

Thus, to say that “Same-sex marriage is not traditional!” comes with the implicit assumption of confining yourself to one or a particular set of cultures. It’s highly traditional in some parts of the world—it just so happens that these traditions are not the dominant ones in the Western world.

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On a lighter note, I recently came across one of the worst arguments I have ever heard in this debate:

To call a homosexual union a "marriage" is to equate it to "traditional marriage," which it is not. Again, this has nothing to do with discrimination, but changing the institution and definition of marriage and violating the first amendment right of freedom of religion. This includes religious expression.

This is so perversely wrong that it’s actually funny. Marriage, as it is currently defined in the United States, is constrained by the rules of the Judeo-Christian cultural background of the European settlers who invaded North America. To allow gay marriage would obviously not infringe on the right of Christians to marry people of the opposite sex. It might offend them, and they might for various absurd reasons feel that it devalues them, but it does nothing to prevent them from engaging in exactly the same religious rituals and religious ceremonies that they already do. It would not affect their rights—only the rights of the same-sex couples who would now be allowed to marry.

If anything (and this is what makes it so perverse), the current laws could be construed as a First Amendment violation! After all, by forbidding same-sex unions, the government is promoting one religion’s view of marriage (the Christian one) over the views of certain other religions (e.g. some African and indigenous North American ones). The current state of things has one religious tradition entrenched in the law—which is precisely what the Establishment Clause of the First Amendment was written to prevent. (I’m not saying that a strong case could necessarily be made that “marriage for heteros only” is an Establishment violation, but if we are to talk violation, it is clearly the case that the status quo favours Christianity, rather than that a change would infringe on anybody’s religious rights.)

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A great deal more could be said on this subject. This is not a piece of advocacy—I’m sure it’s clear that I do advocate recognising same-sex marriages every bit as much as hetero-sex marriages—but the aim here is to discuss some common fallacies and counterfactual claims that have been repeatedly issued in the course of debate. The next time these arise, I will simply provide a link to this post and say, “Here, go see why you are wrong”.

Fallacious: Affirming the Consequent and Denying the Antecedent

The last part in Lisle’s series on logical fallacies is Affirming the Consequent and Denying the Antecedent. (I know these related fallacies as converse error and inverse error, respectively.) Rather to my surprise, he does a very good job of explaining the basic modal logic, modus ponens and modus tollens, and the fallacies themselves, and I won’t spend much time or space here doing what he already did.

In brief, modus tollens (“method of affirming” is the form of argument that runs like this:

	Formal logic	Example
1.	p → q	If I am an atheist, I do not believe in Yahweh.
2.	p	I am an atheist.
3.	∴q	Therefore, I do not believe in Yahweh.

The fallacy of affirming the consequent, or converse error, has the form if p then q; q; therefore p. This is clearly not valid (in the above example, we would get I do not believe in Yahweh, therefore I am an atheist—a conclusion that would surprise non-Abrahamic theists all over the world, not least a billion Hindus).

Similarly, modus tollens or “method of denying” makes another observation from the original premise (here, premise 2 is untrue but the argument is valid, if not sound):

	Formal logic	Example
1.	p → q	If I am an atheist, I do not believe in Yahweh.
2.	!q	I [don’t not] do believe in Yahweh.
3.	∴!p	Therefore, I am not an atheist.

Here, we are at danger of the inverse error, or denying the antecedent, which has the form if p then q; !p; therefore !q. Again the error is fairly clear; the example turns into If I am an atheist, I do not believe in Yahweh; I am not an atheist; therefore I do believe in Yahweh. (The Hindus would again be surprised.)

If my examples don’t make it perfectly clear, you can read Lisle’s article (I can’t believe I just said that), the Wikipedia articles, or find more examples via Google.

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What made me want to write anything about this post of Lisle’s is not his discussion of the fallacies per se, but rather his antiscientific examples, which are slipperier than usual. They demolish strawman positions of science, of course, but the lies are subtler than Lisle’s deceptions usually are. He uses two examples: One attacking the Big Bang theory of cosmology, and the other (of course) evolution. Let us consider the first one. Here’s how Lisle accuses rationalists of committing a converse error:

1. If the big bang is true, then we would expect to see a cosmic microwave background.
2. We do see a cosmic microwave background.
3. Therefore, the big bang must be true.

Lisle correctly points out that this is not a valid logical argument (This big bang supporter has failed to consider other possible causes for the cosmic microwave background). There is no error in this statement. Moreover, it is not an overt strawman as Lisle’s tend to be, in that the argument is in fact very similar to something a rationalist might say. The error, and this is what makes it slipperier, is that we do not present it as a logical argument. A logical argument is one that is fully determined by logic. Unfortunately, this is the province only of mathematicians (and philosophers, if you will, when they stick to things as simple as formal logic—which is really quite mathematical and has been formalised as Boolean algebra, underlying the principles of computers).

When a scientist does cite the cosmic microwave background radiation (CMB) as evidence for the Big Bang, what he’s actually saying is something like this:

1. Before the Big Bang theory was developed, no one suspected the CMB.
2. The theory was developed from other data, and predicted the CMB with a specific temperature of 2.725 Kelvin.
3. Therefore, If the big bang is true, then we would expect to see a cosmic microwave background.
4. No other proposed theory has predicted a CMB.
5. If the theory is not true, then we would not expect to see a CMB.
6. Even if there is a CMB, if the theory is not true, there’s no reason to expect the CMB to have a temperature of 2.725 K.
7. We do see a cosmic microwave background.
8. The CMB does have a temperature of 2.725 K.
9. If the theory had been false, there’s no reason why we should have found this.
10. Therefore, the big bang must be true.
11. When we say “must”, we do not mean that it is a logical necessity, but rather, it is overwhelmingly likely that the theory is ‘true’ in the scientific sense of being a good model for, or interpretation of, what really happened. It made a very specific prediction; it could have been false, but it wasn’t; and no other theory predicted these results.

This is the argument scientists actually make, and unlike Lisle’s version, it is not fallacious.

The philosopher might well say (as might Lisle) that this is a weaker statement than the pure logic above, and this is of course true…but it is an empirical argument, and when we analyse the natural world, it’s what we have to deal with. As empirical evidence goes, this is really a very, very strong case. (It is also, of course, much less than the full case for the Big Bang, which is supported by many lines of evidence.)

Imagine that a doctor listens to your description of your symptoms, predicts that If you have disease X, we should find that you have a fever of 103.2°F, and you turn out to have precisely that: Certainly something else might have caused the fever, but no other proposed hypothesis explains it, and even if some other prognosis did, why should it be exactly 103.2°F if the doctor was wrong? The CMB evidence for the Big Bang theory is of course vastly stronger, because no other astronomical prognosis ever predicted this cosmic background fever at all. A fairer analogy would predict something utterly surprising, straight out of House M.D.; perhaps an organ from an absorbed twin in just such a location…

I will not squander precious blog space by deconstructing Lisle’s attack on evolution in such detail: Suffice to say that it can be deconstructed in a completely analogous manner and is a strawman if precisely the same fibre. The same goes for the first of his alleged examples of inverse error (If we found dinosaurs and humans next to each other in the same rock formation, then they must have lived at the same time; We do not find them next to each other in the same rock formation; Therefore, they did not live at the same time).

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An few interesting asides can be made here:

It is frequently the case that empirical arguments are misunderstood and misconstrued as logical ones. p → q can be read as the logical p implies q, but we could also imagine an empirical, statistical reading: p suggests q. Causation does not imply correlation, but it does suggest it—it does not mean that we can conclude that there is a connection, but it does tell us that there might be one…if we can find that the relationship is systematic, and if we cannot poke holes in it.

I also think that a good case can be made that the scientific method in the traditional sense of hypothesis ⇒ successful test ⇒ theory relies precisely upon attempting modus tollens. Because no knowledge based on observation is absolute, we accept things as true if we attempt to devise ways of disproving them, but consistently fail. A theory is not a hypothesis that must logically be true; it is a hypothesis which makes predictions that are falsifiable in principle, but which consistently stand up to attempts to disprove them.

We may also note from Lisle’s examples that he never actually makes predictions. This is why “creation science” is not actually science: It never stands up and bares its heart to potential falsification. The only time creationists stand up and say Our Biblical view predicts X for any empirically observable fact X is when real science has already predicted or confirmed it. For the most part, creationists seem engaged in a running battle to make their views compatible with whatever scientific theory they cannot simply deny. Unfortunately, to paraphrase somebody presumably brilliant, A theory that excludes nothing, explains nothing. As I have asked before, taking my cue from Jerry Coyne, how would you know if you were wrong?

Insufficient Christianity: Petter’s review

When Ziztur first began to blog about Mere Christianity, I leapt at the chance to read it. I ended up writing a review, which is rather briefer than the chapter-by-chapter dissection that she and Flimsy have posted here. I didn’t want to post it here at the time, because I felt it would be more interesting for blog readers to see the blow-by-blow account, and figured (even back in early June) that I might post my review as a sort of quasi-summary once the project was done and over with. I say “quasi-summary”, because (of course!) this is my opinion, and while it’s pretty similar to theirs, as blogged, I speak for myself, not for them. Nonetheless, it may stand on its own as a briefer review (or dismissal) of the work…

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Over the course of many a fruitless religious debate, one book that my ‘opponents’ have often urged me to read is Mere Christianity by C.S. Lewis. I had never done so, but when I found out that the whole thing was available online (here), I went ahead and read it—in stolen snippets of two days, at that; it’s short and a light read. My very brief conclusion is that C.S. Lewis is an entirely different brand of apologist from the raucous, idiot, Ray Comfort kind to which I have previously been exposed. I get every impression that he was being quite sincere and honest. He may also very well have been intelligent. —I say “may” because this book provides no evidence that he was, but nor do I think that it provides strong evidence that he wasn’t.

That said, in the early chapters of Mere Christianity, comes off as honest, sincere, quite possibly intelligent, and completely unconvincing and to all appearances dead wrong. (This review originally contained a part explaining why I consider it coherent to be intelligent, honest, and completely wrong; that aside grew into this.) So unconvincing and so wrong, in fact, that while I consider it entirely possible that he was intelligent, and while some of his fans may very well be very intelligent (with the same rationale), anyone who was convinced by it must have had their critical thinking faculties shut off for the day. Much as a palæontologist accepts a single fossil or a physicist a single relativistic experiment, you may accept Mere Christianity as fitting into a worldview, but it is no more sufficient to build a complete theory upon. Unlike fossils and physical experiments, however, Mere Christianity attempts logical arguments, and—well, we shall see how it succeeded.

The book is written in a compelling way—easy, conversational language, and a structure where each chapter builds directly and explicitly on the one before it. Thus, he starts off by establishing a universal moral law; shows that the universal law must reflect some underlying reality; shows that this underlying reality must be an Intelligence; shows that it must be an Intelligence rather like the Christian God—and so forth. He is not mealy-mouthed, nor needlessly offensive, nor does he sound insincere. All of this gives me a rather favourable view of him as a person.

As a logician and persuader, however, I can’t give him much respect. My initial reaction to the first few chapters was that, with some minor restructuring, they could easily be retitled according to which logical fallacy he built each chapter’s claim upon. Thus one early chapter took St. Anselm’s failed Ontological Argument and applied it to moral law: We can conceive of a moral law better than our own; therefore there must be a Perfect moral law. (Not true: We might have and fully grasp the ultimate moral law but fail to recognise that it’s perfect.) Another was based on Equivocation (descriptive natural laws with prescriptive moral laws). Another, while not a formal fallacy that I’m aware of, was based on equivocating percepts with objects: That is, he went from All humans feel that there is something rather like X to Therefore, there exists an X with some sort of independent reaction. (Nonsense! If we find that all humans feel X we have indeed discovered a fact, but it’s a fact about human brains, not about the world outside them.) These percepts, once reified, were deified in short order.

Unfortunately, the book went rather downhill from this point. In the early chapters, I can really respect what Lewis was trying to do. Of course, I find that his arguments were not in fact valid, but he clearly believed the premises were true, he obviously believed in his conclusion, and as I have said before and will gladly repeat, it is often very difficult to find flaws in your own inferences when they make a path whereby, as far as you can tell, you get from the right starting point to the right end point. And in these early chapters, I am inclined to agree that if his arguments had been valid and sound, as he believed, then he had some very right and very valuable things to say; and he does lay out his arguments, however flawed, clearly and lucidly.

But this, alas, was not to last. Having once established (in his mind) that there must be a deity that shares some important, basic traits with the god of Judeo-Christian mythology, he went on to implicitly assume a whole slew of Christian dogma, and he did it so suddenly and unselfconsciously that it took me a chapter or two before I went Hang on a minute…! It is as though, once you accept a good, omnipotent creator deity, Moses, the Ten Commandments, Jesus, Judas, and the whole cabaret just followed naturally. This was a huge disappointment—he didn’t even try to show his work in this part of the examination.

The redeeming aspect of this part of the work was that if you once accept his assumptions, a lot of the things he says are very cogent and sensible. But that is not much help if you haven’t accepted those assumptions! He also argues an awful lot by metaphor. This is fine—he manages to explain a number of very weird things in Christian dogma in a way that made a lot of sense to me. So far, so good. However, a critical feature of an explanation by metaphor is that you have to be able to show how it reduces back to the real issue. Again, Lewis doesn’t fail to do this—he never even attempts it. It felt very much as if it never occurred to him that this had to be explained.

And I found this very peculiar, because C.S. Lewis was by all accounts an atheist, and he was brought to believe in all these things. How did this happen? I feel as though he must have had more of a story to tell, because the argument he lays out is completely insufficient to take an intelligent person from atheism to Christianity. Even if his initial arguments had been sound, there just wasn’t a chain of logic available to bring an atheist any further than a sort of nebulous proto-Judeo-Christian monotheism with no specifics of ritual or dogma, let alone such esoteric notions as the Trinity (which, by the way, he explains in lucid, wonderful metaphor that he completely neglects to show to be equivalent to any underlying reality). I supppose Lewis, if he was an atheist before, must not have reached that point by skepticism so much as more specific disappointment with points of dogma.

The part of the entire book that I found the most rewarding to read was, and this might surprise you, the two chapters on Faith. Now, I make it no secret that I regard the concept of faith with derision and contempt—faith, as I generally see it used and defined, refers to belief without evidence, and in some circles (particularly US fundamentalists) even belief in spite of evidence, which is lunacy and the least ethical and virtuous thing you can possibly do without involving others. However, C.S. Lewis defines faith very differently. I can do the concept no better justice than to quote him:

Roughly speaking, the word Faith seems to be used by Christians in two senses or on two levels, and I will take them in turn. In the first sense it means simply Belief—accepting or regarding as true the doctrines of Christianity. That is fairly simple. But what does puzzle people-at least it used to puzzle me—is the fact that Christians regard faith in this sense as a virtue. I used to ask how on earth it can be a virtue—what is there moral or immoral about believing or not believing a set of statements? Obviously, I used to say, a sane man accepts or rejects any statement, not because he wants to or does not want to, but because the evidence seems to him good or bad. If he were mistaken about the goodness or badness of the evidence that would not mean he was a bad man, but only that he was not very clever. And if he thought the evidence bad but tried to force himself to believe in spite of it, that would be merely stupid.

Well, I think I still take that view. But what I did not see then—and a good many people do not see still—was this. I was assuming that if the human mind once accepts a thing as true it will automatically go on regarding it as true, until some real reason for reconsidering it turns up. In fact, I was assuming that the human mind is completely ruled by reason. But that is not so. For example, my reason is perfectly convinced by good evidence that anaesthetics do not smother me and that properly trained surgeons do not start operating until I am unconscious. But that does not alter the fact that when they have me down on the table and clap their horrible mask over my face, a mere childish panic begins inside me. I start thinking I am going to choke, and I am afraid they will start cutting me up before I am properly under. In other words, I lose my faith in anaesthetics. It is not reason that is taking away my faith: on the contrary, my faith is based on reason. It is my imagination and emotions. The battle is between faith and reason on one side and emotion and imagination on the other.

With this second definition of the word faith, it actually makes sense. What this teaches me is that when I next meet someone extolling the virtues of faith, I need to explicitly establish what, precisely, this person means, because he or she may not be referring to it in the sense that I am used to encountering it. If someone believes in the virtues of faith¹, they are beneath being reasoned with. Faith², on the other hand, is in fact a positive thing! I do not need to be persuaded of its virtue; I agree with it! On the other hand, faith² is not a way in which religion can be reached. If somebody tells me that You won’t find God by evidence; you just have to have faith, they are using faith¹ and I will continue to dismiss them. If they take offence at this, I can now not only explain why, but also point out that C.S. Lewis regarded that claim as stupid.

How do you justify your beliefs? Part 2 of 2

In part 1, I divided religious people into fundamentalists and moderates, and noted that fundamentalists have a fairly consistent epistemic basis for their world view: Our Holy Book speaks complete truth, and in areas where it is silent, we must fall back on fallible human science. It is not untroubled, as there are some contradictions in every scripture I’m aware of, but as a basic principle, it is sound. Moderates, who accept such scriptures as “mostly true” or serving as sources of useful truths, but do not accept their complete inerrancy, are in a trickier situation, because in saying that the scripture is less than perfectly true, they have implicitly conceded that its claims are subject to external validation and that the scripture itself is not an authorative source.

God of the gaps

To recapitulate the end of the last post, if the Bible is subject to independent verification, none of its claims that isn’t supported by independent evidence can be taken for granted, and there’s no longer any reason to believe in any of it. Even those who like to see their god in every gap where science has yet to shed light—to claim that he interacts with the world by manipulating quantum uncertainties, for instance, as certain apologists do—have no justification for stretching this (already very flimsy) argument to a specific theistic deity. We can all see how lame an argument it really is: “According to quantum physics, we mere humans can’t tell exactly where that electron is at any given moment; therefore, it may be that God is moving it; therefore, Jesus died for your sins.” Some hand-waving modern theologians claim this; skeptics don’t take them seriously, and neither do fundamentalists, and nor should they.

The God-of-the-gaps argument is, of course, very weak to begin with. By saying that “God acts where science has yet to explore”, your god will shrink into smaller and smaller gaps as science advances—but this is really incidental. More to the point, your god becomes an unfalsifiable claim, and unfalsifiable claims are inherently worthless.

If it isn’t falsifiable, it isn’t true

Strong words: Let me back them up at least a little. It is of course common knowledge that science places great value on falsifiability: We won’t accept a hypothesis, let alone graduate it to the coveted status of scientific theory, unless you can use it to generate falsifiable predictions—in essence saying, “This hypothesis is what I believe; if I’m right, we can run an experiment/look through a telescope/check under a rock and find X; whereas if I’m wrong, we’ll find Y instead.”

But if we think about this for a moment, it’s important not just to science, but to epistemology. If something is not falsifiable—if there’s no hypothetical observation you could possibly make that would lead you to decide that a belief is false—then what you are saying is, in fact, that you can think of no difference between a universe where it is true, and a universe where it is not. What does it even mean to say that something is true, if a universe with or without it are indistinguishable? It certainly doesn’t mean “true” in the sense that I am accustomed to using the word!

Errors in the Bible

Now we get back to these nagging little nitpicking things: Did Judas hang himself, or burst asunder in a field? Does Yahweh, or does he not, plan for some people to be damned? Did he, or did he not, ever change his mind? I agreed earlier that these are incidental things that don’t alter the central message of the Bible, and I wasn’t playing games with you: I believe this is true. It does, however, cast aspersions on biblical inerrancy—in fact, they disprove it. No matter how minor the errors or contradictions may be, if the Bible has any, it’s not an inerrant document, and even if you argue that they are all minor (with which I would not agree), the basis of presumed inerrancy that made it a sound epistemic basis has collapsed. Either you can accept everything the Bible says as fact, or you cannot; since you cannot (without severe cognitive dissonance), you can’t use it as the basis of your epistemology.

If the Bible was wrong about how Judas died, if it disagrees in parts on what such-and-such person said, how can you be absolutely sure that it’s correct on some other matter of what someone said? (Even small errors can change meaning, and it doesn’t get better in translation, let alone multiple translations.) If you can’t be sure whether Yahweh ever changed his mind, or whether some people are predestined for Hell, how can you be sure that Yeshua was his son, that man was created before woman, that…well, anything? Once you admit that the Bible is at all less than perfect, you’re down to saying “Whatever the Bible says is probably true…only some things aren’t, and here are some samples”, there’s no reason to hold any individual claim as necessarily true without independent verification—and so it goes.

Question for the readers

I am genuinely curious, if any of the religious among ye have had the patience, time, and energy to read this far: What is the basis of your epistemology, and how would you falsify your belief? In other words, why do you believe as you do, and what would it take for you to change your mind?

To be fair, I will give a sample of an answer for my own beliefs. I’m tempted to specify what I would need to falsify beliefs in, say, universal gravitation, or the non-existence of fairies, but I’ll play nice and address issues that religionists are in fact likely to disagree with me upon.

For instance, to convince me that my position as an atheist is wrong, a god might show up and blaze writing in burning meteorites across the night sky: “Hey, atheists, I exist!” Or you might find, written in the human genome, encoded in, say, ASCII and English, or Unicode and ancient Hebrew, a message like “This human made by Yahweh, father of Yeshua; all rights reserved”. Or faith healers might develop the ability to actually perform miracles that can’t be explained away—restore lost limbs under laboratory conditions with skeptical magicians like James Randi or Penn and Teller present. There are lots of ways.

On the subject of evolution by natural selection, the famous fossil rabbits in the pre-Cambrian is a good idea. We needn’t go so far, though. The cdesign proponentsist idea of irreducible complexity is not actually a bad one. (As we should expect, they didn’t come up with it but took it from Darwin: Chapter VI of Origin, the famous absurd in the highest degree passage.) If any purportedly evolved structure could be shown to be impossible to produce by gradual evolution, evolutionary theory as we know it certainly could not be true. It’s not an inherently silly idea; it’s just that all of the instances fall flat, and all the evidence is for evolution, so it’s sufficiently unlikely that a solid instance ever be found that I’m comfortable in accepting evolution as a fact. But certainly I can conceive of a difference between a world where evolution is true and one where it is not.

How about you? What do you believe—if differently from me? What is your epistemological justification? And, most importantly, how would you know if you were wrong?

How do you justify your beliefs? Part 1 of 2

As regular readers will have noticed, I have been on a bit of an epistemology spree lately—thinking about thinking, why I believe what I believe, and what logical justification I have for doing so. Now, I’d like to muse out loud on the same topic as applied to religious belief—thus, of course, leaving the subject of what I believe.

To recap what I do believe as a starting point, however: I am a naturalist; I am an empiricist (though not in a philosophically naïve way of assuming that our senses directly report the truth); I believe that the scientific method is the best way of finding truth.

Obviously, religious people as a group believe otherwise, to one degree or another. Many people insist that religious belief is not incompatible with a scientific worldview, but nobody seriously insists that a scientific worldview leads to religion—that there’s real, empirical evidence of Yahweh or Allah or Zeus.

It will be useful for my discursive purposes to divide religionists into two camps, based on their reactions to areas where scientific findings conflict with established religious beliefs. One camp will privelege to science, cede the point, and basically insist that their religion provides truth where science has nothing to say. The other camp will give precedence to their religious beliefs and assert that where there is conflict, the science must be wrong, come hell or high water. The first comprises religious moderates; the second, religious fundamentalists; in particular, I will be talking about fundamentalists of an Abrahamic kind, who believe in the literal truth of the Torah (are there fundamentalist Jews?), Bible, or Qur’an.

Fundamentalists

The fundamentalist camp, for all their various faults, actually has a simple and superficially coherent basis for their epistemology. “Our creed,” they say, “is the Truth; on matters where it will not speak, fallible human science is the best we can do, but knowing that it’s fallible, the Eternal Truth will always trump it.”

And so far as it goes, this seems coherent: The epistemic principle is clear, in any case. It does run into some problems when the creed turns out to contain contradictions. The Christian Bible, for instance, contradicts itself on how many sons Abraham had, whether God wants some people to go to Hell, whether blood sacrifices wash away sin, how Judas died, and a few hundred more… But it has been argued, and at first glance it looks fair, that these are fairly incidental and inessential to the central message.

Unless we look further and find a problem, this worldview seems basically sensible, if you once accept the basic premises—and indeed, it seems largely a matter of premises at this point: The fundamentalist begins with the premise that the Bible is revealed truth; the skeptic, such as I, begins without it. At worst, then, I could accuse the fundamentalist of not looking further (epistemically speaking, anyway).

Religious moderates

Let’s turn aside for a moment and consider the religious moderate, who does not grand automatic primacy to religious claims. We found that the fundamentalist has a fairly coherent basis for his belief system—this, alas, does not seem to be as true for the moderate.

The Christian moderate, for instance, starts from a viewpoint that the Bible contains revealed truth, but must acknowledge that as centuries have passed, scientific progress has been made and much that was once believed to be literally true must be discarded as untrue (or at best metaphorical or allegoric), and much that was once seen as just and right is now considered unjust and wrong.

The need for scriptural inerrancy

I will be the first to applaud the moderate for using reason and moral judgement to figure out what’s true and what’s right rather than blindly accepting some written word or Word on the matter. However, this completely invalidates the Bible as a sole source of truth. —And a religious scripture has a need to stand on its own as a source of truth, because it has nothing to back it up.

We skeptics don’t need authorative sources, indeed we do not hold any source as sacred: We know that the very authority of the most respected source relies precisely on the ability of others to verify that it is correct. We laud Darwin, for instance, as being intelligent and right about an astonishing number of things (however wrong on many details) because other people have come after him, figured out ways to hypothetically disprove him, and found that none of these ways turn out to work. We think that On the Origin of Species is a good book not because it was written by Darwin, but because a century and a half of research, palæontology, experiments, and other books all back up its main thesis.

This is not the case, and indeed cannot be the case, for ‘revealed’ knowledge: The whole point (and definition) of a revelation, in this sense, is that it doesn’t come from something you could have found out by investigating the world. This means that a book of revealed truth is without corroborating evidence, and the most that can be hoped for is a lack of contradicting data. As such, a certain sense of absoluteness hangs about any such scripture. The Bible tells the truth, or it does not tell the truth.

What does it mean, after all, to say that the Bible tells us some things that are true (“there is a god”, “that god is Yahweh of the Hebrews”, “Yahweh had an only begotten son named Yeshua”, “Yeshua was executed to excuse us for the errors of our distant ancestors”), and other things (“the Earth was created in a week”, “it was morally justified to murder babies in the interest of invasion”) are not true? It means that the Bible cannot be taken at face value: If you allow empirical evidence to falsify the Bible, you admit that it’s not inerrant, and any one of its facts may be inaccurate; as such, it’s no longer epistemologically cogent to accept any of its facts without independent verification.

Once you reach this conclusion, the whole enterprise falls apart. If the Bible is subject to independent verification, none of its claims that isn’t supported by independent evidence can be taken for granted, and there’s no longer any reason to believe in any of it. Even those who like to see their god in every gap where science has yet to shed light—to claim that he interacts with the world by manipulating quantum uncertainties, for instance, as certain apologists do—have no justification for stretching this (already very flimsy) argument to a specific theistic deity. We can all see how lame an argument it really is: “According to quantum physics, we mere humans can’t tell exactly where that electron is at any given moment; therefore, it may be that God is moving it; therefore, Jesus died for your sins.” Some hand-waving modern theologians claim this; skeptics don’t take them seriously, and neither do fundamentalists, and nor should they.

This is continued in part 2.

Why Evolution Is True; and cumulative selection

The other day, I picked up Why Evolution Is True by Dr. Jerry Coyne from the library. A few days later I had finished it, and a few days after that, I want to write a few lines on what I think about it.

The book’s aim—as very straightforwardly implied by the title—is to lay out in concise form a reasonably comprehensive (and comprehensible) body of evidence for evolution. As such, it spans a pretty wide range of areas—biogeography, palæontology, genetics, and so forth. At only ~300 pages, it has to go at a pretty good pace, and it does—but it’s largely a good thing. The book is accessible, but not dumbed down; it is brief and concise, but not superficial. It lays out a huge breadth of evidence with plentiful references (many internet references) for those who want more depth.

My brief opinion is: This is one of the best, and possibly the best book I have read in terms of laying out precisely what the title claims: Why Evolution Is True.
 
The funny thing is, when I put it down, my mind was actually full of gripes. I was constantly wondering about the tone—it wasn’t very technical, but couldn’t it have been simplified in places? I now think that, yes, it could have, but I don’t think it would have been to its advantage. It’s simple enough to be accessible to laymen, and that is enough. Let’s not pretend that it isn’t science, don’t give the impression of condescending, and don’t sacrifice precision by avoiding scientific terminology altogether.

I also found one argument missing that I might have liked to see—one that Richard Dawkins has made wonderfully lucid in more than one book—that of the difference between “single-step” and cumulative selection: The counter to the old “747 in a junkyard” argument¹. In fact, its omission irked me very greatly because I think it is such an excellent counter to fairly common creationist/cdesign proponentsist objections to evolution by natural selection as being statistically impossible.

However, I think that the reason why this irked me so very greatly may be because virtually every other persuasive argument is either explained or alluded to; and the focus of the book is, after all, on evidence rather than argument. If someone near you suffers under the delusion that evolution is not a fact, and the neo-Darwinian synthesis is not a very solid scientific theory, you could scarcely do better than to recommend this book to them—perhaps with an explanation of cumulative selection to solidify the deal; or have them graduate to Dawkins, e.g. The Blind Watchmaker, which takes a complementary approach of theoretical argument (though on a very accessible level!) as contrasted to Coyne’s straightforward presentation of evidence.

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¹ The “747 in a junkyard” argument stems from this quote by astronomer Fred Hoyle:

A junkyard contains all the bits and pieces of a Boeing 747, dismembered and in disarray. A whirlwind happens to blow through the yard. What is the chance that after its passage a fully assembled 747, ready to fly, will be found standing there? So small as to be negligible, even if a tornado were to blow through enough junkyards to fill the whole Universe.

Hoyle was not a creationist—but never mind his motivation. Creationists have hijacked this quote and use it to point out a perceived implausibility of evolution. The chance of something so complex as an eye, for instance, arising by chance, is of course minuscule. How can “Darwinists” claim that it arose purely by chance? The answer is, of course, that they don’t, because nobody thinks that the eye sprung forth fully formed from a single mutation, but rather incrementally, and if it was improbable, it was a matter of cumulative selection.

What do I mean by “cumulative probability”? I mean that we can build up on past successes. Take, for example, a coin flip. The odds of getting heads on a single flip is ½. The odds of two flips simultaneously resulting in heads are ½×½ = (½)² = ¼. Three heads at once? ½×½×½ = (½)³ = ⅛. —And so on. The odds of, say, 100 heads all at once are 1 in 2¹⁰⁰: Less than one in a thousand billion billion billion. If we flip our 100 coins once a second, it will take us on the order of a million billion billion years to flip all 100 heads at the same time. That’s about 100,000 billion times the age of the universe. This is single-step selection: We’re looking for a specific result, and we need to get it in a single step: The simultaneous flip of 100 coins.

But natural selection doesn’t require this. The theory of evolution by natural selection predicts that any helpful change will be “saved up” and passed down to further generations—it doesn’t have to be perfect—it just has to be an improvement, however small. If we flip 100 coins, we’ll almost certainly get some heads—the odds of getting 0 are the same as getting 100, and that will virtually never happen. We’ll probably get about 50 heads. Now we’re allowed to save them, and only have to re-flip the 50 tails. Probably about half of them will be heads. —And so forth. If we assume that we get half heads, half tails every time, we’ll have 100 heads—on average—after 7 flips or so.

You will note that 7 is rather less than a thousand billion billion billion. We can now accomplish the task of flipping 100 heads in about 7 seconds rather than 100,000 billion times the age of the universe (if we can sort through them quickly enough…). The argument is vastly simplified, and obviously none of this applies at all closely to biology.

What should be clear—and the point of the argument—is that there is a huge (in fact, a geometrical) difference between single-step and cumulative selection.

Coincidences

Brief IM log snippet:

(10:20:50 AM) David: http://www.youtube.com/watch?v=obIGsb-IZMo&feature=user
(10:22:11 AM) Petter: I paused my music to check that out.
(10:22:28 AM) Petter: In a rather amusing coincidence, the song I paused was a song by Tom Lehrer called "New Math".
(10:22:40 AM) David: wow, what are the odds? ;)
(10:23:10 AM) Petter: Probably inversely proportional to the frequency with which such remarkable coincidences happen to me.

Other peculiar coincidences of my life:

• 
  At a lake, swimming with a friend; we see a column of smoke rising from nearby and make jokes along the lines of I guess I shouldn't have planted that car bomb (yeah, yeah; we were about fourteen). Heading home, we pass the source of the smoke; the burning wreck of a car.
  
• 
  The weirdest one: Playing a role playing game with a friend (same friend, incidentally). The setting is a sci fi one; the game…kind of superhero-ish, a bit like Batman with a lot more guns. Having broken up some crime or other, the hero fires a few rounds into the air to attract the attention of the authorities as he makes his sortie. You accidentally shoot out a streetlight, I declare. Annoyed, he says something to the effect of Oh, come on!, then falls silent as the light bulb in my desk lamp cracks.
• 
  This is the only time in my life I've seen a light bulb do that; I guess thermal expansion and contraction had slowly worked microscopic cracks to the point where most of the glass bulb fell off and shattered on the desk, leaving the screw-in part in the socket, adorned with some jagged pieces of glass.
  

Remarkable coincidences like these seem to tempt some people to commit superstition. Me, I like to wonder the following: What are the odds that anyone should go through life without running into at least a few remarkable coincidences? After all, every single day, every one of us experiences many hundred events (using the term loosely), for a grand total of millions of events over a lifetime. On average, therefore, a person should expect to run into at least a couple of coincidences that are literally one in a million rare; coincidences that are one in a thousand, meanwhile, are a dime a dozen—you'll go through thousands of them. Or, in one of my favoite self-coined phrases, Every single day, on Earth, there are half a dozen people having a one-in-a-billion kind of day.

For a more thorough (but very accessible) discussion of this sort of thing, read Richard Dawkins's Unweaving the Rainbow, in particular chapter 7, Unweaving the Uncanny.

Mental—in the British sense

Over at this blog, an anonymous poster quoth as follows below, and I find it strange and simultaneously amusing and disheartening that people apparently believe in this stuff, according to this reasoning.

Hi ReligionProf, I am paraklete from uncommondescent.com...
I really think that the mind-as-emergent property-of-matter view needs to be thought through some more. When we consider all the different views, from reductive materialism to dualism to emergentism, we need to bring in background information to help us determine which view makes the most sense. From what we know of matter, that it is basically "stuff" that follows natural laws, it is as you know very difficult to see how mental properties - non law like properties - could "emerge" from physical properties. This difficulty does not just appear to be our inability to imagine it, it seems to be based on the very nature of the two phenomena, mental and physical. Not only that, but there's the question of how a network of matter can unify itself into a single stream of consciousness - the "I".

Now on the flip side, when we consider dualism, I believe we have some interesting background information to consider. First, we have a virtually universal ability to conceive of minds without bodies. The vast majority of the world actually believes in minds without bodies, whether it be angels, demons, ghosts, dead ancestors, out of body experiences, and the near universal belief in life after death. Next, we have religious sources telling us about minds without bodies. From the Bible, which you cited regarding Adam, we have a consistent belief in dualism, contrary to what you stated. The psychosomatic unity conception does not at all contradict dualism, for there are forms of dualism that see a deep interweaving of the body and the soul, most notably Thomistic dualism, a view defended by J.P. Moreland in "Body and Soul." For a book that lays out the dualism found in the Bible, I recommend "Body, Soul, & Life Everlasting" by John W. Cooper. Indeed the Hebrew conception of Sheol clearly implies dualism. And Jesus himself was a dualist (e.g. Luke 16:19-31)

So in my opinion, I think the background information should lead us to a dualist view. The only criticism that I have seen against dualism is the "ghost in a box" argument, which basically asks how spiritual substances can interact with physical substances. There does not appear to be any mechansim linking the spiritual to the physical. But I think this is a weak objection, because a child has no problem conceiving of a spirit acting on the physical world, and never does a child think, "Wait, what mechanism is there for this interaction?" The demand for a mechanism is circular reasoning, I think, for a mechanism is itself a physiconcept.

Anyway, those are my thoughts, and I appreciate how you have shared your thoughts with a respectful tone.

What's wrong with this argument, then? Let's go back for a second look…

From what we know of matter, that it is basically "stuff" that follows natural laws, it is as you know very difficult to see how mental properties - non law like properties - could "emerge" from physical properties. This difficulty does not just appear to be our inability to imagine it, it seems to be based on the very nature of the two phenomena, mental and physical.

I am amazed that someone can write out an apparently thought-out argument with this sort of content. Here, he is arbitrarily and a priori assuming that mental phenomena are not physical—referring to mental properties as non law like. In fact, he is using this assumption to further his argument that—mental phenomena are not emergent properties of physical phenomena! This is a circular argument, a tautology: Because A is true, it must be the case that A is true. 

By what reasoning, that does not start with the assumption that dualism is real, can you arrive at the conclusion that it is so? What premises based on observable reality can take you there?
The rest of the stuff (to which I replied over yonder) is less interesting.

Now on the flip side, when we consider dualism, I believe we have some interesting background information to consider. First, we have a virtually universal ability to conceive of minds without bodies. The vast majority of the world actually believes in minds without bodies, whether it be angels, demons, ghosts, dead ancestors, out of body experiences, and the near universal belief in life after death.

—Which tells us that dualism is something that it is easy and tempting to believe in. That does not imply that it is therefore true: It is easy and tempting to believe in a flat earth, too.

There does not appear to be any mechansim [sic] linking the spiritual to the physical. But I think this is a weak objection, because a child has no problem conceiving of a spirit acting on the physical world, and never does a child think, "Wait, what mechanism is there for this interaction?"

Nor does the child think Wait, how can Santa Claus visit all the world's children in a single night? (Well, eventually the child will; it's called growing up. Chew on that one…)

How can you seriously use "children believe it" as an argument for the truth of a statement?
Never mind the religious and supernatural implications. The true tragedy is that this is apparently what to some people passes for intellectual discourse.

Allergies, quackery, and remarkable cures

I recently received an email from an acquaintance, whom I shall not name here, on the subject of allergies (people who know me tend to bring that subject up now and then). Anything I represent as a quote below will actually be a paraphrase either to clarify or to disguise certain characteristic writing traits.
Here follows a snippet from the first email in our exchange:

Here is one of the articles (I find it very interesting):
http://www.healingdaily.com/detoxification-diet/enzymes.htm
This is from there:

It was found that after a person eats cooked food, his/her blood responds immediately by increasing the number of white blood cells. This is a well-known phenomena called 'digestive leukocytosis', in which there is a rise in the number of leukocytes - white blood cells - after eating.
Since digestive leukocytosis was always observed after a meal, it was considered to be a normal physiological response to eating. No one knew why the number of white cells rises after eating, since this appeared to be a stress response, as if the body was somehow reacting to something harmful such as infection, exposure to toxic chemicals or trauma.

Apart from the fact that the authors of the website do not know that phenomena is the plural form of the noun, we can’t learn a whole lot from this, but the briefest of perusals of the website demonstrates it to be a hotbed of quackery, some of it dangerous. As I said in my initial reply,

That website is, unfortunately, full of shit. Some of it is actually very dangerous. Chelation -- which they seem to think is just *great* -- is a favourite of alternative medicine people, but it's a terrible idea.

[I’m snipping a lot of stuff here—if you want to know what I think about chelation, ask.]

…chelation therapies are toxic. […] Another interesting fact is that […] chelation therapy will leech [sic] calcium from your body and may lead to hypocalcemia. This can cause you to stop breathing or cause cardiac arrhythmia, in really bad cases…
…I won't take my medical advice from people I *know* to be full of shit.

I consider this a useful caveat—the website contains stuff that makes sense to me, but that doesn’t prevent some of it from being shit, and as a single source it’s therefore useless.
Now, the problem is that although the website, in all fairness, does contain a reasonable description of what an allergy is, my acquaintance took away something rather different, judging from my acquaintance’s reply, email #3 in the sequence:

The whole point is that by eating properly, and giving your body the food it will be happy with, and not junk it with stuff such as doughnuts, dead burgers, and cooked tasty food (just because we like it), you will strengthen the natural fighting mechanism of your body, which is not now fuctioning properly in most humans, because it is always busy fighting dead food.

There is a terrible irony here, because an allergic reaction is an immune response—an immune response to what I call spurious pathogens, which is my trumped-up way of saying it’s triggered by the wrong things; when I go into anaphylactic shock from exposure to peanut butter, it’s because my immune system thinks I’ve taken poison and is doing all it can to rid me of it (unfortunately killing me in the process). The immune system is therefore not too weak in a person with allergies; it’s responding too strongly!

In fact, some very interesting research has generated the hypothesis that the reason why allergies are so prevalent in the hypersanitised Western nation is because we are, in a sense, too healthy. Carl Zimmer describes this beautifully in his book Parasite Rex. The brief gist of it (as I understand it) is that our immune system helps us fight off viruses, bacteria, and parasites in general. Therefore, parasites have evolved mechanisms to suppress our immune system. In response, evolution comes to supercharge our immune system to cope with the parasites’ chemical weaponry; they escalate in turn…and so on, for a few million years, until modern living virtually eliminates whole arrays of parasites and leaves us with supercharged immune systems without the dose of immunosuppressants they would normally be hampered by. Hence, it may be, they go haywire.

And this isn’t just crazy talk. It’s real science, and experiments have been performed, including one study (also here) where test subjects were deliberately infected with (controlled doses of) hookworms, and experienced relief of allergy symptoms.

There’s a kind of terrible backwardness throughout this entire discussion so far, such as when my sparring partner in discussion asks

Would you rather eat dead but safe food, or live and energetic (perhaps with traces of nature's dark side as parasites)?

Need I mention that the most energetic of foods are ones high in quick carbohydrates, simple sugars, and fats? Need I point out that vegetables are good for you not because they are energetic, but specifically because they are low in energy density? Apparently I do. As for the dark side…

The ironic thing is that this person and I could probably largely agree on what constitutes a healthy diet, but the mode of thinking is completely different. But then, I do not generally engage in debate to dispute (specifically) a conclusion, but rather flaws in reasoning. Any foolish way of thinking may lead you accidentally to the right answer, but relying on it is dangerous. This is the same thing that leads to other alternative medicine treatments—I will not use the word cures to describe them. Alternative medicine kills. (Chelation therapy can certainly kill.) Detoxification and colon cleansing kill, too. Even raw food diets have ended up killing people—children—when people failed to apply critical thought.

That is why I am proud to consider myself a skeptic, and that is why I will never abide terrible reasoning, even when no conclusions have ended up catastrophic—yet.

Epistemological pragmatism: Skeptical thinking in a resource-limited world

This ties in to my last post on skepticism and the scientific method as a way of thinking. I apologise if this reads as dense and amateurishly philosophical, but to me, it is important to examine not just what I believe, but also—and in fact much more importantly!—why I believe it, and whether that “why” makes sense. If it doesn’t, I have some serious reconsidering to do…

As skeptics, we know that the scientific method is a good way to look at the world. We know that logic trumps intuition, that successful prediction beats rationalisation; we know the logical fallacies people tend to make; and by arming ourselves with an understanding of cognitive biases, we can conquer them in the areas where we are ourselves most vulnerable. We are perfectly well aware that knowledge requires scientific investigation, and we certainly know that the Argument from Authority is a logical fallacy most foul.

And yet we found much of our knowledge on authority.

Is this true? How can it be? How can it be justified? How can we know anything, if we do something we know to be a fallacy?

It is, of course, true. The simple fact is that the world is a very complicated place. If there ever was a time when anyone could master the sum of human knowledge, it was countless millennia ago, and it certainly far predated the scientific method. While we as a species learn more and more, the fraction of all human knowledge that any one person can have consequentially grows smaller and smaller. Darwin probably knew all about evolutionary biology even apart from that which he set down, but to understand it all today you would have to catch up on 150 years of research. Want to understand physics? After you’ve mastered calculus and differential equations, I have a few hundred books to help get you started…

So while we can set up a set of principles whereby we know that knowledge can rationally be attained, economy of scale dictates that no one person will ever learn all about everything he needs to know. Even someone with a doctorate is only an expert in a narrow sub-field of one particular field of one scientific discipline. This narrow but deep knowledge, hard-earned with experiments and comprehended (we may hope) from first principles, is indeed the gold standard to which we would like to hold knowledge in general—but because we have jobs, because we have other things to do, and because we can’t expect to live more than 80 years or so, there’s no way we can actually apply that standard to most of our lives.

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So what can we do? Well, we can do precisely what we are doing: Rely on credible experts, use good judgement, and so forth. These things, however, fall lamentably short of the lofty goals alluded to above, and at first glance look suspiciously like precisely those practices we abhor: Argument from Authority, raising personal experience (or anecdotal evidence, or case series, …) above proper science, and so forth. I argue that this is not equivalent, and I shall defend my position. All the same, I will be the first to admit that this limitation is a weakness.

Using good judgement and relying on credible experts is all very well and good, but suffers from a bit of a chicken-and-egg problem. It’s difficult to judge whether a purported expert is credible or a loon when he claims expertise in a field you know nothing about. If the papers are available, that won’t help you much when you’d need a decade of studies and a Ph.D. to understand the mathematics and the lingo.

The first thing we have to ask, when we face any claim, is How do you know it is true? Even if you know nothing of the subject, it is often possible to determine whether principles are based on reality or lunacy. Here is my guideline:

Given two alternative explanations, where one claims a scientific explanation and cites purported evidence and the other does not, prefer the scientific explanation. 

This is simple and obvious, but I think it’s fairly powerful. If I’m just critical enough to check if there is a plausible explanation, I can rule out wide swaths of nonsense—even in fields where I am not qualified to judge the details of anyone’s explanations or assess the reliability of anyone’s data! If I catch two oncologists discussing the relative merits of radiation therapy versus chemotherapy in a heated manner, each waving tables and research publications, I have little or no hope of assessing whose argument is stronger. However, I can reasonably assert that each of them is better at treating cancer than, say, an acupuncturists, because at least they have explanations that may very well be true, whereas the acupuncturist hasn’t a leg to stand on.

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Sadly, that rule, however valuable, can only rule out the very wildly nonsensical. What if you are faced with a dilemma where you have to put your trust in one of several opposing viewpoints but you lack the expertise to rule any of them out as implausible? What if, for instance, I have to make a life-or-death choice to go with one and only one of my hypothetical oncologists? This may be a little more controversial, but I’m going to recommend that you put your trust in the scientific consensus. Of course, it’s very true indeed that the majority opinion—even of experts—can be wrong, but this is not quite so major a problem as it may appear at first glance.
The common objection is Science has ‘changed its mind’ many times in the past—how can you be sure that it won’t happen again? In fact, it probably will, so you’ll most likely turn out to be wrong! 

First, while some “brave mavericks” with wild new ideas turn out to be right, most of them turn out to be wrong (and are soon forgotten, which is why this fact is not so obvious). Especially in alternative medicine, a lot of people seem to consider themselves the rebels bucking the staid establishment, comparing their ostracisation from mainstream medical culture to the persecution of Galileo—but To wear the mantle of Galileo, it is not only necessary to be persecuted: It is also necessary to be right. (Alternatively: True, they laughed at Galileo—but they also laughed at the Marx brothers.)

Second, some fields—notably medicine—were pretty horrible before the 20th century or so. It’s often argued that homeopathy gained traction in the first place because mainstream medicine at the time was so dangerous that it was better to go untreated—thus homeopathy, by doing nothing, avoided doing the harm a normal doctor would have done. However, we may have some confidence that this is no longer the case because we actually do statistics now. We can compare mortality rates for treated versus untreated people suffering some condition, so we know that modern medicine (though far from perfect!) is in fact better (in a very large number of cases, vastly better) than doing nothing. Thus, the scientific consensus today is superior to the scientific consensus 200 years ago by the first principle above—the modern one relies on solid principles, the old one did not.

Third, most scientific improvement is gradual. It is not the case that every paradigm shift means that everything that went before it is bullshit. I will be the first to agree that Einstein’s model of the universe with time as a dimension rather than a metaphysical constant, where everything is relative to the speed of light, and gravity is modelled as spacetime curvature rather than Newton’s unexplained attraction—this is a very wonderful model and in fundamental ways very superior to the Newtonian model. But that doesn’t mean that Newton was dead wrong! In fact, he was pretty close in many respects—close enough to launch spacecraft and send them to other planets. This gradual progress means that while

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Finally, when dealing with an individual claim, we can get an idea of somebody’s credibility in areas where we lack the expertise to assess his claims directly by building a picture of his credibility in fields where we can assess it. Of course, a person could in principle be simultaneously a pathological liar and a brilliant scientist, but in our day-to-day lives, when we have to assess whether a specific claim made by a specific person, we’ll never take a known liar on his word. Strictly speaking, this is an ad hominem argument: I seem to suggest that you reject claims based not on what is in them, but the negative traits of the person making them! This isn’t quite true; I’m not categorically rejecting such claims, but I reject them coming from untrustworthy people. If I hear the same claims coming from someone I judge to be credible, I will of course reconsider.

The other half of the above equation is, to reiterate, to judge a person’s credibility based on the claims in areas where we can assess them. Someone who is in the habit of making claims on subjects he knows nothing about—well, he may not exactly be lying, but you know that he is disqualified as a reliable authority. If you can ascertain whether he has a track record of being right (or being wrong) in areas related to the subject at hand, this can build an even more detailed picture.

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Of course, if you are faced with a purported expert who, for all you know, is generally very credible indeed, who makes a claim you are personally incapable of verifying or falsifying, based on what seems to you to be a solid, scientific backing…he may well be wrong, or misleading you. It’s not a perfect world, and no one is or ever was perfect. No amount of scientific thinking guarantees infallibility; what the scientific method does offer us is, at best, an asymptotic approach to the truth. We use it not because it is perfect, but because there are no better alternatives.