Abstract
Suppose that a scientific theory X is well confirmed, and either states or implies a statement like “classes exist”. Suppose, if the statement is not explicit but implied, that the specified systems are ‘accepted’ by two individuals, R and F, as the ‘best available'. Suppose, finally, that both R and F, in some yet to be explained sense of the word, ‘accept’ and use theory X to regulate their experience. Then we have something very like the situation discussed by Putnam and van Fraassen in their debate over ‘fictionalism'. I will argue that, in this situation, there is a great mystery over what would separate a fictionalist F from a realist R. Neither Putnam nor van Fraassen seems to be conscious of the problems involved.Fictionalism, according to its opponent, Putnam, statesvarious entities presupposed by scientific and common sense discourse [are] merely “useful fictions”, or that we cannot, at any rate, possibly know that they are more than “useful fictions”.
