How does science work?

For the moment, I am presenting this as a question.  It is a question for which I believe I have the answer.  But I will postpone discussing that until future posts.

I am currently watching (for the second time), a TED talk by David Deutsch:

• David Deutsch: A new way to explain explanation

In that video, Deutsch is puzzling about what changed at the time of the scientific revolution.  He correctly points out that people have been making observations and coming up with explanations for thousands of years.  We often describe their explanations as myths.  Something must have changed in what we are doing, that made science possible.