Online research in philosophy

In a recent paper in this journal, Mark Balaguer develops and defends a new version of mathematical fictionalism, what he calls ‘Hermeneutic non-assertivism’, and responds to some recent objections to mathematical fictionalism that were launched by John Burgess and others. In this paper I provide some fairly compelling reasons for rejecting Hermeneutic non-assertivism — ones that highlight an important feature of what understanding mathematics involves (or, as we shall see, does not involve).

In this paper we introduce a distinct metaethical position, fictionalism about morality. We clarify and defend the position, showing that it is a way to save the 'moral phenomena' while agreeing that there is no genuine objective prescriptivity to be described by moral terms. In particular, we distinguish moral fictionalism from moral quasi-realism, and we show that fictionalism possesses the virtues of quasi-realism about morality, but avoids its vices.

Questions about necessity (or what has to be, or what cannot be otherwise) and possibility (or what can be, or what could be otherwise) are questions about modality. Fictionalism is an approach to theoretical matters in a given area which treats the claims in that area as being in some sense analogous to fictional claims: claims we do not literally accept at face value, but which we nevertheless think serve some useful function. However, despite its name, “Modal Fictionalism” in its usual manifestations is not primarily fictionalism about claims of necessity and possibility, but rather a fictionalist approach to claims about possible worlds. (For instance, modal fictionalism is not normally fictionalist about the claim that “it is possible that there be a species of tail-less kangaroo”, but rather about the claim that “there is a possible world in which there is a species of tail-less kangaroo”.) The practice of taking possible worlds to be merely convenient fictions, or of treating talk about possible worlds as being useful without being literally correct, is quite common in philosophical circles. It is only recently, however, that philosophers have seriously examined the implications of taking possible worlds to be merely fictional objects, like Sherlock Holmes or a frictionless surface.

This paper responds to John Burgess's ‘Mathematics and Bleak House’. While Burgess's rejection of hermeneutic fictionalism is accepted, it is argued that his two main attacks on revolutionary fictionalism fail to meet their target. Firstly, ‘philosophical modesty’ should not prevent philosophers from questioning the truth of claims made within successful practices, provided that the utility of those practices as they stand can be explained. Secondly, Carnapian scepticism concerning the meaningfulness of metaphysical existence claims has no force against a naturalized version of fictionalism, according to which our ordinary standards of scientific evidence may show that we have no reason to believe the mathematical existence claims made within the context of our mathematical and scientific theories.

This paper develops a novel version of anti-platonism, called semantic fictionalism. The view is a response to the platonist argument that we need to countenance propositions to account for the truth of sentences containing `that'-clause singular terms, e.g., sentences of the form `x believes that p' and `σ means that p'. Briefly, the view is that (a) platonists are right that `that'-clauses purport to refer to propositions, but (b) there are no such things as propositions, and hence, (c) `that'-clause-containing sentences of the above sort are not true-they are useful fictions. Semantic fictionalism is an extension of Hartry Field's mathematical fictionalism, but my defense of the view is not analogous to his. One of the many virtues of my defense is its generality: it explains how we can adopt a fictionalist stance towards all abstract singular terms, e.g., mathematical singular terms and `that'-clauses.

In this paper I outline an alternative to hermeneutic fictionalism, an alternative I call indifferentism, with the same advantages as hermeneutic fictionalism with respect to ontological issues but avoiding some of the problems that face fictionalism. The difference between indifferentism and fictionalism is this. The fictionalist about ordinary utterances of a sentence S holds, with more orthodox views, that the speaker in some sense commits herself to the truth of S. It is only that for the fictionalist this is truth in the relevant <span class='Hi'>fiction</span>. According to the indifferentist, by contrast, we are simply non-committal – or indifferent – with respect to some aspects of what is literally said in our assertive utterances (specifically, with respect to the ontologically committing aspects).

Gideon Rosen’s [1990 Modal fictionalism. Mind, 99, 327–354] Modal Fictionalist aims to secure the benefits of realism about possible-worlds, whilst avoiding commitment to the existence of any world other than our own. Rosen [1993 A problem for fictionalism about possible worlds. Analysis, 53, 71–81] and Stuart Brock [1993 Modal fictionalism: A response to Rosen. Mind, 102, 147–150] both argue that fictionalism is self-defeating since the fictionalist is tacitly committed to the existence of a plurality of worlds. In this paper, I develop a new strategy for the fictionalist to pursue in response to the Brock–Rosen objection. I begin by arguing that modal fictionalism is best understood as a paraphrase strategy that concerns the propositions that are expressed, in a given context, by modal sentences. I go on to argue that what is interesting about paraphrastic fictionalism is that it allows the fictionalist to accept that the sentence ‘there is a plurality of worlds’ is true without thereby committing her to the existence of a plurality of worlds. I then argue that the paraphrastic fictionalist can appeal to a form of semantic contextualism in order to communicate her status as an anti-realist. Finally, I generalise my conception of fictionalism and argue that Daniel Nolan and John O’Leary-Hawthorne [1996 Reflexive fictionalisms. Analysis, 56, 26–32] are wrong to suggest that the Brock-Rosen objection reveals a structural flaw with all species of fictionalism.

Hermeneutic fictionalism about mathematics maintains that mathematics is not committed to the existence of abstract objects such as numbers. Mathematical sentences are true, but they should not be construed literally. Numbers are just fictions in terms of which we can conveniently describe things which exist. The paper defends Stephen Yablo’s hermeneutic fictionalism against an objection proposed by John Burgess and Gideon Rosen. The objection, directed against all forms of nominalism, goes as follows. Nominalism can take either a hermeneutic form and claim that mathematics, when rightly understood, is not committed to the existence of abstract objects, or a revolutionary form and claim that mathematics is to be understood literally but is false. The hermeneutic version is said to be untenable because there is no philosophically unbiased linguistic argument to show that mathematics should not be understood literally. Against this I argue that it is wrong to demand that hermeneutic fictionalism should be established solely on the basis of linguistic evidence. In addition, there are reasons to think that hermeneutic fictionalism cannot even be defeated by linguistic arguments alone.

It is often assumed without argument that fictionalism in the philosophy of science contradicts scientific realism. This paper is a critical analysis of this assumption. The kind of fictionalism that is at present discussed in philosophy of science is characterised, and distinguished from fictionalism in other areas. A distinction is then drawn between forms of fictional representation, and two competing accounts of fiction in science are discussed. I then outline explicitly what I take to be the argument for the incompatibility of scientific realism with fictionalism. I argue that some of its premises are unwarranted, and are moreover questionable from a fictionalist perspective. The conclusion is that fictionalism is neutral in the realism-antirealism debate, pulling neither in favour nor against scientific realism.

Abstract: It is often assumed without argument that fictionalism in the philosophy of science contradicts scientific realism. This paper is a critical analysis of this assumption. The kind of fictionalism that is at present discussed in philosophy of science is characterised, and distinguished from fictionalism in other areas. A distinction is then drawn between forms of fictional representation, and two competing accounts of fiction in science are discussed. I then outline explicitly what I take to be the argument for the incompatibility of scientific realism with fictionalism. I argue that some of its premises are unwarranted, and are moreover questionable from a fictionalist perspective. The conclusion is that fictionalism is neutral in the realism-antirealism debate, pulling neither in favour nor against scientific realism.