Let’s say we are looking at a tree and it looks like it has ten apples growing on it. I say “That tree has ten apples.” and you say “No, it doesn’t. Not necessarily.” I say “What do you mean?” and you say “You can’t know for sure. Maybe there is an invisible apple on it that won’t be detected until science reaches a more profound understanding of the the nature of light and the nature of apples, and that won’t happen until you and I are dead, many, many thousands of years in the future.”
You are being a skeptic, and a lot of philosophers since Descartes have argued that is no way to be, and have tried to articulate just what mistake you are making.
I remember hearing Hillary Putnam argue once, in a lecture on pragmatism (although I may misremember), that when I say “there are ten apples on the tree” what I mean is “If science continued for the next 10 to the 100 years –an inconceivable time for humans — far longer than the age of the universe from Big Bang to heat death — we would have no reason to believe there were any more or less than ten apples on that tree.” So if I say that there are ten apples on the tree I’m right. That’s what apples being on a tree means — that given our understanding of an unimpeded growth of science into an indefinite, but not infinite future, we will have no reason to think otherwise.
That is definitely one way of assuring that I’m right. Except for the problem that when I say there are ten apples on the tree, I don’t mean that. I just mean that there are ten apples on the tree. And I might be wrong.
It seems like the pragmatist impulse is one way of protecting against failure. It tries to make the goal of statements like “there are ten apples on that tree” more limited and human and humble, so as to avoid the anxiety of total failure. Another way is to just make the statements and fess up to the fact that they may fail.
Let’s call these two approaches the “pragmatist” and the “fallibilist”.
Which is a better way of coping with the possibility of failure? They are both attempts to achieve a sort of cognitive humility, and therefore like all attempts at humility, are prone to morphing into their opposite. The pragmatist endeavors to be humble about the use of his concepts, but if he becomes proud of his humility he seems to make a dubious claim to have an extraordinary insight into what we really mean by ordinary words like “know” and “apple”. The fallibilist endeavors to be honest about our mistakes but if he becomes proud of his humility he seems to have discovered something amazing: that we don’t know anything.
Is there a way of making sure for once and for all that our humility will not degenerate into false-humility? There may be somebody out there who knows the way, but if you meet him don’t tell him he does, as this will surely go to his head.