Why Science Should Stay Clear of Metaphysics
Philosophers of science are not known for agreeing with each other—contrariness is part of the job description. But for thousands of years, from Aristotle to Thomas Kuhn, those who study what science is have roughly categorized themselves into two basic camps: “realists” and “anti-realists.”
In philosophical terms, “anti-realists” or “empiricists” understand science as investigating the properties of observable objects via experiments. Empirical theories are constrained by the experimental results. “Realists,” on the other hand, speculate more freely about the possible shape of the unobservable world, often designing mathematical explanations that cannot (yet) be tested. Isaac Newton was a realist, as are string theorists.
Most scientists do not lose sleep worrying about philosophical divides. But maybe they should; Albert Einstein certainly did, as did Niels Bohr, and Erwin Schrödinger. In the 20th century, Kuhn’s cataloguing of the “paradigmatic” nature of scientific revolutions entered the scientific consciousness. As did Karl Popper’s requirement that only theories that can in principle be determined to be false are scientific. “God exists,” for example, is not falsifiable.
But outside the halls of the academy, the influential works of philosophers of science, such as Rudolf Carnap, Wilfrid Sellars, Paul Feyerabend, and Bas C. van Fraassen, to list but a few, are little known to many scientists and the public.
As the inventor of “constructive empiricism,” van Fraassen is widely acknowledged by his peers as one of the greatest living philosophers. (He calls himself “a philosopher’s philosopher.”) Van Fraassen does not write for the philosophically uninitiated, but his books are in no danger of going out of print.
“In 1980, van Fraassen’s singlehandedly changed the terms of the debate between scientific realism
