I need to get clearer about the rationality of beliefs versus the rationality of actions. One question is whether it is ever rational to believe something for which one has insufficient evidence. And if it is never rational to believe something for which one has insufficient evidence, then presumably it is also never rational to act upon such a belief. For example, if it irrational to believe in God and post-mortem survival, then presumably it is also irrational to act upon those beliefs, by entering a monastery, say. Or is it?
W. K. Clifford is famous for his evidentialist thesis that "It is wrong always, everywhere, and for anyone, to believe anything on insufficient evidence." On this way of thinking, someone who fails to apportion belief to evidence violates the ethics of belief, and thereby does something morally wrong. Although Clifford had religious beliefs in his sights, his thesis, by its very wording, applies to every sort of belief, including political beliefs and the belief expressed in the Clifford sentence lately quoted! I take this as a refutation of Clifford's evidentialist stringency.
If I took Clifford seriously I would have to give up most of my beliefs about politics, health, nutrition, economics, history and a crapload of other things. For example, I believe it is a wise course to restrict my eating of eggs to three per week due to their high cholesterol content. And that's what I do. Do I have sufficent evidence for this belief? Not at all. I certainly don't have evidence that entails the belief in question. What evidence I have makes it somewhat probable. But more probable than not? Not clear! But to be on the safe side I restrict my intake of high-cholesterol foods. It's a bit like Pascal's Wager. What I give up, namely, the pleasures of bacon and eggs for breakfast every morning, etc. is paltry in comparison to the possible pay-off, namely living and blogging to a ripe old age.
And then there is a problem whether Clifford has sufficient evidence for his evidentialist thesis. It is obvious to me that he doesn't but I'll leave that for the reader to work out.
Consider now the case of a man dying of thirst in a desert. He comes upon two water sources. He knows (never mind how) that one is potable while the other is poisonous. But he does not know which is which, and he has no way of finding out. Should the man suspend belief, even unto death, since he has insufficient evidence for deciding between the two water sources?
On one way of looking at the matter, suspension of belief would clearly be the height of irrationality. The desert wanderer must simply drink from one of the sources and hope for the best. Clearly, by drinking from one (but not both) of the sources, his chances of survival are one half, while his chances of survival from drinking from neither are precisely zero. By simply opting for one, he maximizes his chances of reality-contact, and thereby his chances of survival. Surely a man who wants to live is irrational if he fails to perform a simple action that will give him a 50-50 chance of living when the alternative is certain death.
Cases like this are clear counterexamples to theories of rationality according to which rationality requires always apportioning belief to evidence. In the above case the evidence is the same for either belief and yet it would be irrational to suspend belief. Therefore, rationality for a human agent (as opposed to rationality for a disembodied transcendental spectator) cannot require the apportioning of belief to evidence in all cases, as Clifford demands. There are situations in which one must decide what to believe. Will I believe that source A is potable? Or will I believe that source B is potable? In Jamesian terms, the option is live, forced, and momentous. (It is not like the question whether the number of ultimate particles in the universe is odd or even.) An adequate theory of rationality, it would seem, must allow for believing beyond the evidence. It must return the verdict that in some cases, to refuse to believe beyond the evidence is positively irrational.
Let us consider another such case. What evidence do I have that my new neighbors are decent people? Since they have just moved in, my evidence base is exiguous indeed and far from sufficient to establish that they are decent people. (Assume that some precisifying definition of 'decent' is on the table.) Should I suspend judgment and behave in a cold, skeptical, stand-offish way toward them? ("Prove that you are not a scumbag, and then I'll talk to you.") Should I demand of them 'credentials' and letters of recommendation before having anything to do with them? Either of these approaches would be irrational. A rational being wants good relations with those with whom he must live in close proximity. Wanting good relations, he must choose means that are conducive to that end. Knowing something about human nature, he knows that 'giving the benefit of the doubt' is the wise course when it comes to establishing relations with other people. If you begin by impugning the integrity of the other guy, he won't like you. One must assume the best about others at the outset and adjust downwards only later and on the basis of evidence to the contrary. But note that my initial belief that my neighbors are decent people — a belief that I must have if I am to act neighborly toward them — is not warranted by anything that could be called sufficient evidence. Holding that belief, I believe way beyond the evidence. And yet that is the rational course.
So again we see that in some cases, to refuse to believe beyond the evidence is positively irrational. A theory of rationality adequate for the kind of beings we are cannot require that belief be always and everywhere apportioned to evidence.
And now we come to the Big Questions. Should I believe that I am libertarianly free? That it matters how I live? That something is at stake in life? That I will in some way or other be held accountable for what I do and leave undone? That God exists? That I am more than a transient bag of chemical reactions? That a Higher Life is possible?
Not only do I not have evidence that entails answers to any of these questions, I probably do not have evidence that makes a given answer more probable than not.
But here's the thing. I have to believe that I have a higher destiny if I am to act so as to attain it. It is like the situation with the new neighbors. I have to believe that they are decent people if I am to act in such a way as to establish good relations with them. I have to believe beyond the evidence.
Suppose I'm wrong. I live my life under the aegis of God, freedom, and immortality, but then one day I die and become nothing. I was just a bag of chemicals after all. It was all just a big joke. Electrochemistry played me for a fool. So what? What did I lose by being a believer? Nothing of any value. But if I am right, then I have done what is necessary to enter into my higher destiny.