It is natural for people to want to be certain of things, and not just the theological things discussed in the last chapter. Uncertainty about anything can be very uncomfortable. It is an uncomfortable feeling not to be certain whether the car will make it the last thirty miles home on the petrol in the tank-uncomfortable, that is, if one does not have the money to buy more, or if there is nowhere to buy it from. (Some people find situations like this one exciting, but these people have other problems. They are the kind of people who climb mountains and leap unprovoked out of aeroplanes. Perhaps, though, part of the legitimate exhilaration and challenge of these activities is achieving certainty and control over great danger.) And so it is natural to want to know in advance, in a general way, of what one can be certain. If I am not entitled under any circumstances to feel certain about how much petrol is in the tank, because I cannot see how much there is, and this for the general philosophical reason that I can only be certain about what I can see, then I ought in consistency to feel uncomfortable about making it home even when I have just filled the tank. So I ought to feel uncomfortable all the time about everything I cannot see. Is this right?