Deferentialism and the Territory of Philosophy Author: Terence Rajivan Edward, University of Manchester. Abstract. David Liggins and Chris Daly have argued against a recent trend in which some philosophical debate or other is said to be settled by claims from a discipline other than philosophy, because claims from that discipline entail a position on the debate and any claims from that discipline have greater authority than any philosophical claims when the aim is to extend our knowledge. They label this trend deferentialism. This paper presents a dilemma for their argument. 'Deferentialism' is a term which David Liggins and Chris Daly use to refer to a recent trend in philosophy, a trend which they are against. The trend involves attempting to settle this or that philosophical debate by deferring to another discipline. The other discipline is said to make claims that entail a position on a philosophical debate and to have an authority that philosophy does not, when the aim is to extend our knowledge. The nature of that discipline means that claims from it are more justified than claims from philosophy, or so it is asserted. Consider, for example, the debate over whether or not philosophical idealism is true: whether or not everything is either a mind or something mind-dependent. Imagine someone arguing that this philosophical debate can be resolved by appealing to physics. Idealism is false because it is incompatible with claims from physics and claims from physics carry a greater authority than any philosophical considerations. In this example, philosophy is expected to defer to physics when evaluating idealism. The trend which Liggins and Daly are focusing on does not just involve drawing attention to a claim from another discipline, saying that this claim entails a position on a philosophical debate and saying that we should defer to this discipline, because claims from it have greater authority than claims from philosophy. It also involves representing the debate as something that can be resolved without philosophy. Deferentialists write as if philosophy is not needed to justify any of these moves. The purpose of this paper is to identify a major concern about Liggins and Daly's way of arguing against deferentialism. Their argument is that deferentialism should be rejected because it has weaknesses and these weaknesses are avoidable at little or no cost, because of a certain alternative position available. They articulate this alternative as follows: Although the evidence drawn from some non-philosophical disciplines is relevant to many philosophical debates (as naturalism claims), such evidence cannot alone settle any philosophical debate. Scientific claims, for example, take their place as only one kind of data in such debates, and they are not necessarily the most important or the most established kind... Resolving those debates involves weighing up many kinds of data and many methodological considerations by means of an often protracted and difficult cost-benefit analysis. (2011: 322) As I understand them, Liggins and Daly recommend this alternative because it preserves the strength of deferentialism – it allows philosophy to take into account relevant evidence from other disciplines – but it avoids the four weaknesses that they believe deferentialist doctrines suffer from, weaknesses that it is not necessary to detail here. Their argument against deferentialism is intended to be a philosophical argument and my reading of their argument fits with their conception of how philosophy is done: by weighing up the benefits and costs of different positions and supporting the position with the greatest benefits and the fewest costs. When arguing against deferentialism, Liggins and Daly never clarify what a philosophical debate is, despite using the term 'a philosophical debate' to say what deferentialism is and to formulate their alternative to it. This absence plays a part in my objection to them, but it is not the whole objection. My objection requires a bit of preparatory work before it can meaningfully be introduced. Assume, for the sake of argument, that there is a question which is debated in journals that are classified as philosophy journals and is debated by people who are paid to do philosophical research, as part of this research, yet which can in fact be resolved by deferring to another discipline. If you encounter such a debate, you might say that the debate cannot be a genuine philosophical debate. It appears to some people to be a philosophical debate, but that appearance is an illusion. If you respond like this, it sounds as if you are operating with an understanding of what a philosophical debate is which rules out deferential solutions to them. For example, your understanding might be captured by the following propositions: (i) A philosophical debate is a debate about a philosophical question. (ii) A philosophical question is a question that, if it can be resolved at all, cannot be resolved without relying on philosophical methods. (iii) Philosophical methods are non-empirical methods that are not mathematics. For instance, to argue using a non-mathematical deduction from self-evident premises would be to employ a philosophical method. Liggins and Daly, however, cannot clarify what a philosophical debate is in a way which entails that deferentialism is a mistaken, because then their argument against deferentialism would be pointless. The very definition of a philosophical debate would exclude the possibility of deferential solutions to such debates, removing the need to argue against deferentialism by identifying its weaknesses and then showing that these weaknesses are avoidable. But a clarification with this consequence looks to be a good way of explaining what they have in mind by a philosophical debate. In the quotation below, which reports the beliefs of deferentialists, they give some examples of philosophical debates: These philosophers variously believe that such philosophical problems as whether numbers exist, whether composition is unrestricted, or whether ethical sentences are declarative sentences are settled once and for all by evidence drawn from outside of philosophy. (2011: 322) Why are these debates philosophical debates? At least one of the debates, whether ethical sentences are declarative sentences, may at first sight appear to be a debate that belongs to linguistics, not to philosophy, even if it matters for the classically philosophical concern with whether morality is subjective or objective. Presumably, the reason for counting this debate as a philosophical debate is that, if it can be resolved at all, philosophy is needed to resolve it. But if Liggins and Daly give this reason, then they are committed to the kind of clarification which renders their argument pointless. We are now ready to make an objection. Liggins and Daly are faced with a dilemma: either their argument against deferentialism is pointless, because the very definition of a philosophical debate entails that there are no deferential solutions to such debates, or else it is obscure, because it is unclear what they mean by 'a philosophical debate' – we do not know what we are assenting to if we assent to their claim that no philosophical debate can be settled by deferring. Reference Daly, C. and Liggins, D. 2011. Deferentialism. Philosophical Studies 156: 321-337.