Fundamental observation of science
I had a post a way back about fundamental theorems of certain branches of mathematics. This post is about what I think is the fundamental observation of science. Ready? The fundamental observation of science is:
Repeated observations are more reliable than unrepeated ones.
Why is that? Basically, that is because people are unreliable. I have memories of things I can prove to myself never happened, or happened quite differently from what I remember. How do I know? Well, the time I am thinking of involves me doing something rather unthinkable that could have potentially killed my brother. I firmly remember it as being on accident, but I also know that this memory has been reconstructed at least once in my head. I actually have two different memories of the event. I know that a particular one of them is wrong, because nobody could run as fast as I remember my brother running in that one.
Other times, I've made stuff up out of thin air. Why? Because it seemed advantageous at the time. Like that I only had "one" piece of candy for desert. That I had done my homework, but forgot it at home (might have said that more than once, and I'll bet it was a lie at least 99% of the time).
It stands to reason that this kind of thing happens to other people too sometimes. Maybe some people are more reliable than me. Maybe some people never lie. Maybe some people are never deceived by their senses or their memories. Maybe some people have perfect intuition or never make a logical mistake. Unfortunately, it's hard to reliably tell who those people are.
So, if we can't trust any single person, can we ever gain a reliable picture of the world? The laws of nature? The gross history of the universe? I think our best bet is to get rid of single points of failure in the system.
A certain codification of this philosophy is called science. An experiment is a procedure you can repeat any number of times to give an observation that either rejects or is consistent with a hypothesis. You can be as sure as you like which is the case by repeating the experiment enough times. A hypothesis is scientific if you can show that if it's false then there is some experiment that rejects it.
That isn't, by far, enough to define science. In fact, it's just one aspect. Science is fundamentally a creative endeveor. When does a hypothesis become accepted as being a probable fact? At least it needs to go through a reasonable period of scrutiny in which people try to show that it's false based on some experiment, or that it's somehow infeasible to do the experiments.
But serious scientists insist on not allowing single mistakes from forever corrupting the conclusions. This is related to the value of skepticism, which says that it's better to be unsure than to be sure and wrong.