about truth
Sometimes, as scientists and philosophers, we tend to become a bit pedantic in our use of certain words, especially those we are particularly fond of. One of those words is proof.
Ever since the philosophies of Hume and Kant undermined the foundations of knowledge, there has been a steady disintegration of confidence in all sources of knowledge, but especially in the sciences. It is not at all uncommon today to hear scientists say things like, "nothing is ever really proved in science," or "science is not really concerned with proof."
It is true that proof is not the main purpose of science. The main purpose is discovery. Proof is not part of science until scientists believe they have discovered something, like a new phenomenon or an explanation for something. The purpose of proof is to determine if a proposed discovery really is what it is presumed to be.
Since critics of science, and many scientists as well, have taken this dim view of proof, the whole field of science has suffered. One result has been a proliferation of pseudo-scientific claims, which, so long as "proof" is not required, receive just as much respect as legitimate science. The other result is that legitimate science and scientists have lost one of the guiding principles of science.
The most damaging result of the repudiation of proof, is a prevailing and general opinion that there is really no proof of anything. It is one of the dominant symptoms of the anti-intellecual spirit of our age.
What is Proof?
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Everyone uses the word proof from time to time and in most cases everyone knows exactly what they mean.
When my wife asks, "Honey, did you leave the keys in the car?"
And I answer, "I'm sure I didn't. I always take them out of the ignition when I get out of the car."
The proof comes when, in a little while I hear, "Honey, I found the keys."
"Oh really. Where?" I ask, cautiously.
"In the car," she says, nonchalantly.
My wife had a theory1 my keys were in the car; I had a theory they were someplace else; when my wife found the keys in the car that was proof her theory was correct and my theory was wrong.
This illustrates what proof means in everyday language. All other supposed meanings are either refinements of this everyday meaning, or esoteric meanings pertaining to special cases.
Since this is only an illustration, we should define the everyday meaning of proof as follows:
Proof: Something which demonstrates what we suppose is the case is actually the case, and therefore, true.2
"Something which demonstrates," can be anything so long as it accomplishes the task of demonstrating the supposition or proposition is actually true. It could be a logical argument, an experiment, or simply presenting a specimen of a fact, for example.
"What is supposed is true," is any proposition, usually in the form of a statement or series of statements, that asserts something (a quality, characteristic, a relationship, or existence itself, for example) about something else (an entity, event, concept, or relationship, for [next page]