Being rational means being resistant to wishful thinking. Unfortunately for us, we are rather prone to wishful thinking. It is also unfortunately the case that there are lots of people out there who know about our propensity for wishful thinking and would like to exploit it. Animal communication systems, as Robert Trivers famously noted, did not evolve to produce truth but to procure reproductive advantages for the communicators. For human animals, swindling people out of wealth and loyalty are a pretty good way to get advantages. So if you want to be rational and resist such forces, you should apportion your skepticism about any claim such that, the more it would be good for you if that claim were true, the more skeptical of it you ought to be.
Concrete illustration: consider three claims.
Claim A: Spreading WonderVegeGreen on your lawn will make it lovely, thick, and lush!
Claim B: Taking Ironized Yeast will cure your common cold!
Claim C: This drug made from apricot pits will cure your cancer!
Ask yourself, just intuitively, which of these claims ought we to be most skeptical of? Which would most be likely to induce wishful thinking? If it looks like a ladder for skepticism, you’re doing well with rationality.
The view that we ought to apportion our skepticism against our propensity for wishful thinking I call the Snake Oil Dispersant. Snake Oil claims are what it is there to rid us of. (For those unfamiliar with the term, “snake oil” was a generic term for mystery medicines peddled by itinerant salesmen in nineteenth century America. These medicines would supposedly cure a wide range of ailments which the real medicine of the day was largely powerless against.
The claims of things like religion ought to be something like Claim Z on my ladder: real snake oil in need of being dispersed. What could we want more desperately to believe than with all the suffering in the world and in our lives, that somehow we are getting (or at least, potentially can get) something (a blissful eternal afterlife, or “meaning”) that somehow makes it all worthwhile. Many among us, seeing how the brutal and nasty so often prosper in the world, while the kindly and gentle are trodden underfoot, might also long for some sort of justice in the world. But precisely because we so long for such things is why we should be burningly skeptical of any claims that such states of affairs could ever, in fact, be realized — that is, we should be skeptical of precisely the claims that religions advance.
The claims of religion are notoriously weak even against mild skepticism, a fact which goes a long way to explaining my incredulity with respect thereto.
Though I don’t mean to bash religion only. Snake-oil dispersant ought to be liberally deployed against forms of secular optimism as well. Both trite and untrue folk beliefs (“If you work hard and play by the rules, you’re sure to succeed,” “There’s somebody out there for everyone”) or grand secular substitutes for religion, such as humanism or transhumanism are unlikely to survive much contact with skepticism. It’s all to easy to somehow want to believe, as humanists would have us do, that life is “meaningful” even in spite of the fact that it’s often so miserable, or that in some glorious future we’ll all live in some amazing awesome virtual reality. Maybe that’s sad. So be it. It is not a property of truth that it is here to make us happy.