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© 2024. All rights reserved.
Site created with
Hakyll.
Modified theme
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based on
Lanyon.
Twentieth century philosophers were very concerned about making sense of “theoretical terms”, i.e. new words in science that aren’t part of common vocabulary. It’s easy to come up with examples of such terms — from “germ” to “gene” to “atom” and “electron”. And it’s easy to see why scientifically-minded philosophers would be anxious about such concepts. If we got rid of trolls, fairies, angels and gods because they are unobservable, then why do we so blithely accept other unobservable things such as electrons, protons, and quarks?1
For all its intrinsic interest, Niels Bohr wasn’t concerned with this issue about introducing new concepts into science. In fact, Bohr comfortably adopted the language of “atoms” and “electrons” and eventually “quantum fields”. However, Bohr was extremely concerned about a different issue of how we use language to do science: how to take words that we already know and learn how to apply them (unambiguously!) in domains that are wildly different from those we are familiar with. To take a classic example from Wittgenstein: “what time is it on the surface of the sun?”2 The word “time” is a part of everyday language, so there is no question of giving meaning to a new word. Instead the question is: can we continue using this word in this unfamiliar context? And if so, do we need to be aware of any new subtleties that might put us in danger of getting confused about how to use this word?
This concern of Bohr’s — old words in new contexts — is displayed most clearly in his discussions of the concepts of position and momentum.
There’s a long, interesting story here. Rudolf Carnap’s thinking on theoretical terms lasts his entire career — and ranges from attempts at explicit definition, to partial reduction, and then to the use of Ramsey sentences. Carnap’s attitude toward theoretical terms was also a main focus of Quine’s criticism (in “Two dogmas of empiricism” and other places). Unfortunately, Quine took Carnap’s concern to be motivated exclusively by sceptical, empiricist considerations — making Carnap into more of a British empiricist. Quine seems to have missed Carnap’s very practical concerns about how to get all of the scientific concepts to hang together in an intelligible system, and about making decisions about which theories are best. Many philosophers of the late 20th century bought Putnam’s arguments to the affect that there is no good definition of “theoretical term”, and so the whole thing is a pseudo-problem.↩︎
As far as we know, Bohr wasn’t aware of Wittgenstein’s example; and Wittgenstein was largely unaware of Bohr’s thoughts on the language of science.↩︎