The further we progress in knowledge, the more clearly we can discern the vastness of our ignorance.
Karl Popper
The principle of science, the definition, almost, is the following: The test of all knowledge is experiment. Experiment is the sole judge of scientific "truth." But what is the source of knowledge? Where do the laws that are to be tested come from? Experiment, itself, helps to produce these laws, in the sense that it gives us hints. But also needed is imagination to create from these hints the great generalizations -- to guess at the wonderful, simple, but very strange patterns beneath them all, and then to experiment to check again whether we have made the right guess.
Richard Feynman
I had been a student of philosophy and of the "problem of knowledge" so-called for many years; but this was the first time I had observed that "finding out" is not after all the same as knowledge; that the thing found out is truly known only when published, spread abroad, communicated, made effective in the common life, a bond of union among men. We come back, whether we would or no, to the primitive, the human, sense of truth: truthfulness ¡V generous, frank efficiency of communication. Truth, in final analysis, is the statement of things "as they are," not as they are in the inane and desolate void of isolation from human concern, but as they are in a shared and progressive experience. Friends, said the Greek proverb, have all things in common. Truth, truthfulness, transparent and brave publicity of intercourse, are the source and the reward of friendship. Truth is having things in common.
John Dewey, "The Problem of Truth." (1911) In The Middle Works of John Dewey, vol. 6, ed. Jo Ann Boydston (Carbondale: Southern Illinois University Press, 1978), p. 67.
What we call 'reality' is in large measure a papier mache construction, an immense labour of imagination and theory filled in between the iron posts of observation.
John Wheeler
I've often thought there ought to be a manual to hand to little kids, telling them what kind of planet they're on, why they don't fall off it, how much time they've probably got here, how to avoid poison ivy, and so on. I tried to write one once. It was called Welcome to Earth. But I got stuck on explaining why we don't fall off the planet. Gravity is just a word. It doesn't explain anything. If I could get past gravity, I'd tell them how we reproduce, how long we've been here, apparently, and a little bit about evolution. I didn't learn until I was in college about all the other cultures, and I should have learned that in the first grade. A first grader should understand that his or her culture isn't a rational invention; that there are thousands of other cultures and they all work pretty well; that all cultures function on faith rather than truth; that there are lots of alternatives to our own society. Cultural relativity is defensible and attractive. It's also a source of hope. It means we don't have to continue this way if we don't like it.
Kurt Vonnegut, Jr.
Facts are meaningless. You can use facts to prove anything that's even remotely true.
Homer Simpson
When I have to choose between the true and the beautiful, I choose the beautiful.
Hermann Weyl