Some nice examples of correct predictions being a necessary but not sufficient criteria to prove a model is correct (see also http://astrorhysy.blogspot.com/2016/04/perfectly-wrong-or-necessary-but-not.html).
For example, when Niels Bohr predicted in 1913 the correct frequencies of the specific colours of light absorbed and emitted by ionised helium, Einstein reportedly remarked: "The theory of Bohr must then be right."
Bohr's predictions could instantly persuade Einstein (and many others besides) because they were correct to several decimal places. But they came out of what we now know to be a deeply flawed model of the atom, in which electrons literally orbit the atomic nucleus in circles. Bohr was lucky: despite his model being wrong in fundamental ways, it also contained some kernels of truth, just enough for his predictions about ionised helium to work out.
But perhaps the most dramatic example of all concerns Arnold Sommerfeld's development of Bohr's model. Sommerfeld updated the model by making the electron orbits elliptical and adjusting them in accordance with Einstein's theory of relativity. This all seemed more realistic than Bohr's simple model... scientists working in the early 20th century thought of electrons as very tiny balls, and assumed their motion would be comparable with the motion of actual balls.
This turned out to be a mistake: modern quantum mechanics tells us that electrons are highly mysterious and their behaviour doesn't line up even remotely with everyday human concepts. So Sommerfeld's theory had a radical misconception at its very heart. Yet, in 1916, Sommerfeld used his model as the basis for an equation that correctly describes the detailed pattern of colours of light absorbed and emitted by hydrogen. This equation is exactly the same as the one derived by Paul Dirac in 1928 using the modern theory of relativistic quantum mechanics.
Despite the fact that later evidence proved these theories wrong, I don't think we should say the scientists involved made mistakes. They followed the evidence and that is precisely what a good scientist should do. They weren't to know that the evidence was leading them astray.
These few examples certainly shouldn't persuade us that science can't be trusted. It's rare for evidence to be very misleading and, usually, radically false theories don't produce successful, accurate predictions (and usually they produce radically false predictions). Science is a process of constant refinement, with a knack for ironing out unhelpful twists and turns in the long run. And we all know that even the most trustworthy can occasionally let us down.
https://phys.org/news/2018-06-evidence-scientists-decades.html
Very good. Especially that bit about the treatment of Occam's Razor as just another sharp, pointy implement.
ReplyDeleteAnd there stands Pilate, confronted by a platoon of dogmatic Bearded Wonders, yelling at them "What is truth?" Truth is only as much as the evidence suggests.
It seems that truth may sometimes be betrayed by the presence of evidence that is for some reason inadmissible. I find myself struggling to provide fair evidence of this truth. I shall endeavor to liberally bludgeon this point with a blunt instrument until it has been beaten into a plowshare.
ReplyDeleteThe thing is that we can't ever demonstrate that a theory is true/correct in a global sense. We can validate specific predictions and establish a domain of validity. Then, the theory can be considered useful within that domain of validity.
ReplyDeleteNewtonian mechanics has a domain of validity and it remains useful when applied within that. Calling any theory true or correct seems philosophically clumsy and inapt.