In my last entry, I pointed out that we all simply have to take a leap of faith when we believe that the world is real, and not a dream. The leap of faith was a large part of the work of the philosopher Søren Kierkegaard, and is also a reoccurring theme in the movie Inception. My chapter, in my book Inception and Philosophy: Because It's Never Just a Dream (published by Wiley-Blackwell) considers this question: When should we take a leap of faith?
Faith is often heralded as a virtue, something noble, something you should have. But clearly this is not always true. In the movie, Cobb asks Mal and Saito to take a leap of faith-to believe that their world is not real and to kill themselves so they can wake up. Cobb takes a leap of faith to believe that Saito can deliver on his promise to get Cobb's charges dismissed. Yet when Mal asks Cobb to take a leap of faith-out of his hotel window-he doesn't. And we don't think he should; we don't' think it's a good idea. (Although, if they were dreaming...) So, obviously, we don't think that faith is always virtuous. It's not always something you should have or act on.
What is faith? Some think it is simply belief, but that can't be right-I don't believe by faith that the world is round. I have good evidence. In fact, that seems to be what sets faith apart. Faith is belief without sufficient evidence. It can come in degrees. On the basis of faith, you might believe something that you have little or no good reason to believe. On the basis of faith, you might also believe something that you have good reason to believe is false. I'm inclined to think that most people would agree that this latter kind of faith-we might call it "blind faith"-is not virtuous. It certainly isn't rational to continue to believe something (that vaccinations cause autism, for example) when you have very good reason to think that it is false (autism rates are not higher in vaccinated children, and all positive evidence has been exposed as fraudulent). But maybe believing something that you can't prove false can be virtuous or rational.
The philosopher Bertrand Russell didn't think so, though. In an article that was too controversial to be published in his time, he gave the famous example of the celestial teapot. Suppose I believed, without good reason, that there was a tiny tea pot orbiting the sun between Earth and Mars. It's so small, in fact, that no telescope could ever see it. So, you can look all you want with your telescopes, and not see a teapot, but that will never count as evidence against my belief. "Of course you can't see it," I will say, "It's too small." You could never prove that such a tea pot doesn't exist. But belief-faith-that such a teapot exists is still clearly irrational. And it certainly isn't virtuous.
What's the point? Russell's point is that, when it comes to belief in the existence of something, the burden of proof is on the believer. If I want to believe in the celestial teapot, I have to provide evidence for its existence. If I cannot, then belief that the teapot exists is not rational. Russell was trying to draw an analogy with religious belief. (That's why the article was so controversial.)
What's my point? I don't think people actually believe that faith is a virtue. Belief in the teapot would require faith-belief without evidence-but no one would think it is virtuous. The virtue of faith is often touted in religious circles, but usually people don't think that it's virtuous to believe the tenets of other religions by faith-only one's own. What's virtuous is "believing the right thing." So, when people say that faith is a virtue, they really don't think that it's the "belief without evidence" part that is virtuous. They just think that believing the right thing is virtuous. I would agree. Of course, the trouble is figuring out what the right thing is.
I do think there are some things that it is rational to believe by faith-to believe without evidence. Hume taught us, for example, that it is impossible to have evidence for the reliability of induction. Induction is a type of reasoning that assumes that the future will resemble the past. "Since the sun has risen every day in the past, it will rise tomorrow as well." We can't prove such reasoning is reliable. I could try by pointing out that it has been reliable in the past and from this concluding that it will be reliable in the future. But that, itself, is an inductive argument that extrapolates about the future from the past. I can't use an inductive argument to prove the reliability of induction; that's arguing in a circle. We simply have to assume that induction is reliable. In short, we have to believe in the reliability of evidence itself, without evidence. We have to take it on faith.
But I think that is okay. Einstein defined insanity as "doing the same thing over and over again and expecting different results." In other words, if you don't think the future will resemble the past, you're crazy! In fact, try living without that assumption. Try believing that the next time you put your hand on the hot stove, it won't hurt. You can't do it. Since it's impossible to avoid such a belief, and rejecting it would entail that you are crazy, I'd say that belief in induction by faith is rational.
But not all faith is rational, as we have already seen. Belief that the dream sharing technology of Inception is real is not rational, even though I could never prove that it is not real. You may feel certain it isn't real, but how could you prove that idea was not incepted into you by someone using the dream share technology? Likewise, even if there weren't better explanations for ghosts and UFO experiences (which there are), belief in ghosts and UFOs would not be rational. (If you do think such belief is rational, I highly recommend Ted Schick's How to Think About Weird Things.) Just like with Russell's celestial teapot, unless you have good evidence for something's existence, you shouldn't believe that it exists.
So should Cobb have believed that Saito could get his charges dismissed? It probably wasn't rational. But it might have been practical; the benefits might have been worth the risk. And maybe, when people believe something by faith, that is all they are concerned about: not about being rational, but about reaping the rewards of belief. One must always be careful, though. As William Clifford taught us, belief without evidence that risks harm to others is immoral. Has anyone harmed someone because of something you believe by faith? Have you? The faith that Cobb calls Mal and Saito to causes them to commit suicide. Sometimes, faith can be a dangerous thing.