Science is usually criticized for one of two contradictory things.
Either scientists are so blindly accepting of How Science Says Things Are that they cannot be trusted to make judgments about stuff like flying saucers and ESP and the ghost of Elvis.
Or else scientists are so uncertain of How Things Really Are that it just proves that any hypothesis — flying saucers, ESP, the ghost of Elvis — is as good as any other.
Now, granted, some scientists are as enamored of knowing The Truth that they do get blinded by it. But most scientists are not, I’d say, and even those verging on that accept the scientific method: hypothesize based on what you’ve proven, develop an experiment to test the hypothesis, disprove the hypothesis or move onward.
Scientists do occasionally discover stuff that was hypothesized, and even widely accepted, is not true. Now that may be happening again. Some new experiments are hinting that a hypothesized subatomic particle called the Higgs boson — which has conveniently fit into quite a bit of the picture physicists have draw about the fundamental nature of matter and energy — may not actually exist.
The point to this is not that scientists don’t really know anything. If that were so, this computer wouldn’t exist. What it does mean is that scientists don’t know everything — and that good scientists are willing to change their worldview as the evidence changes.
As Isaac Asimov once put it:
The young specialist in English Lit … lectured me severely on the fact that in every century people have thought they understood the Universe at last, and in every century they were proved to be wrong. It follows that the one thing we can say about our modern “knowledge” is that it is wrong.
… My answer to him was, “… when people thought the Earth was flat, they were wrong. When people thought the Earth was spherical they were wrong. But if you think that thinking the Earth is spherical is just as wrong as thinking the Earth is flat, then your view is wronger than both of them put together.”
— Isaac Asimov (1920-1992), in The Relativity of Wrong (1996)
(Via Xkot)