Yeah, I’m not a fan of this framing. (Love the YANNS podcast, though!)
The introductory example in the book is that in 1953 we believed that there were 48 chromosomes in the human genome, and now we know there are only 46. But that doesn’t mean the facts changed.
The statement “there are 46 chromosomes in the human genome” was true in 1953. And it’s true today.
The statement “the best available scientific evidence in 1953 was that there are 48 chromosomes in the human genome, so people believed that” was true in 1953. And it’s true today.
The fact that people didn’t realize that the first statement was a fact in 1953, but did know in 1956, doesn’t change the validity of the statement. It just means they were wrong.
Facts don’t change. The degree to which we know and understand them, and the magnitude of our certainty, does. That’s not the same thing, though.
And the idea of a “half-life” of our beliefs about the facts (not the facts themselves) seems pretty goofy to me. You’d have to stretch any definition of the word “fact” past the point of sensibility for anything remotely like it to be true. I took a lot of physics between 1984 and 1990. If the half-life of physics “facts” is 13 years, only 25% of what I learned about physics should still be regarded as correct. But no, sorry, that’s bullshit. Newtonian mechanics still works as a perfectly good approximation of the motion of physical bodies at non-relativistic speeds. The relativistic corrections we’ve known about since the 1930s still work. We’re learning more about sub-sub-atomic particles and confirming that the weirder things in the Standard Model are actually there, but everything I learned about protons and neutrons and electrons and quarks is still considered correct. Electricity and magnetism aren’t different. Statistical mechanics isn’t different. The Schrodinger and Dirac equations still work, and the experimental support for them is still valid.
So where’s the 75% of what I learned about physics a quarter century ago that isn’t true? There isn’t any.
