I want to test your wits, but to do so you have to promise to play fair. As most folks know, I am something of an anti-realist about science (in a very loose sense of "anti-realism"), and I have blogged often about the relationship between theory and observation and how perspectives in the working scientist can influence that relationship (this was, indeed, a theme behind my most recent posts on the "verification" of the miraculous). I have come across various statements of this theme in a wide variety of authors, from the usual suspects such as Bas Van Fraassen and Paul Feyerabend to some less obvious but perhaps for that even more interesting suspects such as Ernst Cassirer and Pierre Duhem, but recently I came across a version of this theme in a writer in whom I was quite surprised to find it, and I am wondering if anyone will be able to guess who it is.
When I say you have to play fair, what I mean is this. I'm going to offer some quotations from this author relevant to this theme, and I want you to try to figure out who the author of these quotations is, but of course you could easily discover it simply by Googling these quotations, because this author is very famous--so famous, in fact, that I'm quite sure that you have all heard of this person and, indeed, I would be willing to bet money that all of you have read at least one book by this person. So to play this game I must ask that you not use Google or any other electronic resource. Instead, rely on your wits and, if possible, your memory, or perhaps your collection of books or a good library. But if you think you know who the author of these quotations is, let me know in a comment, and I will announce the winner (the first person to correctly identify the source) as soon as we have one.
Now, on to the game. Here are the quotations, all from relatively close together in the one book from which they are all drawn. At the end of the post I will give some hints.
In every age it will be apparent to accurate thinkers that scientific theories, being arrived at in the way I have described, are never statements of fact. That stars appear to move in such and such ways, or that substances behaved thus and thus in the laboratory--these are statements of fact. The astronomical or chemical theory can never be more than provisional. It will have to be abandoned if a more ingenious person thinks of a supposal which would 'save' the observed phenomena with still fewer assumptions, or if we discover new phenomena which it cannot save at all.Some hints. The author is no longer living. The author was an expert in a particular academic field but also wrote popular works, both in the author's own field and in other fields. As I have already mentioned, it is extremely likely that you have already read at least one of this author's books, and I imagine that it is also likely that the book that you read was a work of fiction.
This would, I believe, be recognized by all thoughtful scientists today. It was recognized by Newton if, as I am told, he wrote not 'the attraction varies inversely as the square of the distance', but 'all happens as if' it so varied. It was certainly recognized in the Middle Ages. 'In astronomy', says Aquinas, 'an account is given of eccentrics and epicycles on the ground that if their assumption is made (hac positione facta) the sensible appearances as regards celestial motions can be saved. But this is not a strict proof (sufficienter probans) since for all we know they could also be saved by some different assumption.' The real reason why Copernicus raised no ripple and Galileo raised a storm, may well be that whereas the one offered a new supposal about celestial motions, the other insisted on treating this supposal as fact. If so, the real revolution consisted not in a new theory of the heaves but in 'a new theory of the nature of theory'.
Note, too, that there are still some scientists out there who seem to want to treat their "supposals" as facts. One thinks, for example, of Richard Dawkins, but there are others who do the same.
More hints: The author wrote, in addition to scholarly articles and books, in more than one genre of fiction, including science fiction and fantasy. One of these works was made into a movie, and the author was also the subject of a book that was turned into a movie.