When I hear scientists talk about Thomas Kuhn, he sounds very reasonable. Scientists have theories that guide their work. Sometimes they run into things their theories can’t explain. Then some genius develops a new theory, and scientists are guided by that one. So the cycle repeats, knowledge gained with every step.

When I hear philosophers talk about Thomas Kuhn, he sounds like a madman. There is no such thing as ground-level truth! Only theory! No objective sense-data! Only theory! No basis for accepting or rejecting any theory over any other! Only theory! No scientists! Only theories, wearing lab coats and fake beards, hoping nobody will notice the charade!

I decided to read Kuhn’s The Structure Of Scientific Revolutions in order to understand this better. Having finished, I have come to a conclusion: yup, I can see why this book causes so much confusion.

At first Kuhn’s thesis appears simple, maybe even obvious. I found myself worrying at times that he was knocking down a straw man, although of course we have to read the history of philosophy backwards and remember that Kuhn may already be in the water supply, so to speak. He argues against a simplistic view of science in which it is merely the gradual accumulation of facts. So Aristotle discovered a few true facts, Galileo added a few more on, then Newton discovered a few more, and now we have very many facts indeed.

In this model, good science cannot disagree with other good science. You’re either wrong – as various pseudoscientists and failed scientists have been throughout history, positing false ideas like “the brain is only there to cool the blood” or “the sun orbits the earth”. Or you’re right, your ideas are enshrined in the Sacristry Of Settled Science, and your facts join the accumulated store that passes through the ages.