Daniel Nolan

The question of what truths are necessary in the broadest possible sense is a difficult one to answer, as is the question of what the limits are to what is possible. (Most people would see these two questions as different sides of the same coin, of course, since many think the question of what is possible is just the question of what is not necessarily ruled out). We have three general sorts of strategies for determining whether something is necessary (or possible). We can identify it in a class that we were previously sure was a class of things that are necessary – we might show it is a theorem of a logical system that we have confidence in, or that the sentence appears to be true simply in virtue of the meanings of the words, or that it is a true statement involving names or about natural kinds of the “necessary a posteriori” sort discussed by Kripke and Putnam, and there are perhaps other classes of claims which we are prepared to accept are necessary if true.1 Likewise, we might establish the possibility of something occurring by reference to a class of well-established or uncontroversial possibilities: e.g. we are inclined to think that it is possible (in the broadest sense) for an event to occur in the future if one of the same kind has occurred in the past.

Many people want to hold that some theoretical virtues—simplicity, elegance, familiarity or others—are only pragmatic virtues. That is, these features do not give us any more reason to think a theory is true, or close to true, but they justify choosing one theoretical option over another because they are desirable for some other, practical purpose. Using pragmatic virtues in theory choice apparently brings with it a dilemma: if we are deciding what to accept on the basis of considerations that are not truth-conducive, it looks like we should either refrain from believing what we accept, and adopt some sort of instrumentalist attitude to the theories we cherish; or alternatively, we stand charged with engaging in theoretical irrationality in our belief formation. This paper discusses the appropriate response to this dilemma

One increasingly popular technique in philosophy might be called the "platitudes analysis": a set of widely accepted claims about a given subject matter are collected, adjustments are made to the body of claims, and this is taken to specify a “role” for the phenomenon in question. (Perhaps the best-known example is analytic functionalism about mental states, where platitudes about belief, desire, intention etc. are together taken to give us a "role" for states to fill if they are to count as mental states.) We then look to our best theory of the world to see where this role is satisfied, if at all. Unfortunately, the platitudes analysis, so characterised, does not seem to help when we are doing fundamental metaphysics—when we want to know what, at base, our world is like (and not merely where things like e.g. the mental would be found in an already-specified ontology). Nevertheless, I will argue that the platitudes analysis, properly understood, does have the materials to help us answer questions in fundamental metaphysics as well. I will explore three different ways it can do so.

Reasoning about situations we take to be impossible is useful for a variety of theoretical purposes. Furthermore, using a device of impossible worlds when reasoning about the impossible is useful in the same sorts of ways that the device of possible worlds is useful when reasoning about the possible. This paper discusses some of the uses of impossible worlds and argues that commitment to them can and should be had without great metaphysical or logical cost. The paper then provides an account of reasoning with impossible worlds, by treating such reasoning as reasoning employing counterpossible conditionals, and provides a semantics for the proposed treatment

One of the standard approaches to the metaphysics of personal identity has some counter-intuitive ethical consequences when combined with maximising consequentialism and a plausible doctrine about aggregation of consequences. This metaphysical doctrine is the so-called ‘multiple occupancy’ approach to puzzles about fission and fusion. It gives rise to a new version of the ‘utility monster’ problem, particularly difficult problems about infinite utility, and a new version of a Parfit-style ‘repugnant conclusion’. While the article focuses on maximising consequentialism for simplicity, the problems demonstrated apply more widely to a range of ethical views, especially flavours of consequentialism. This article demonstrates how these problems arise, and discusses a number of options available in the light of these problems for a consequentialist tempted by a multiple occupancy metaphysics

The work which the Loeb Classical Library classifies as book 3 of the Oikonomika attributed to Aristotle is a curious piece. It has come down to us only via medieval translations into Latin. (I will be quoting the Loeb text and translation except where noted.) It is not certain that it is by Aristotle: and it is not certain whether it is even a part of the work attributed to Aristotle in ancient times. For want of a better name, let me refer to its author, whoever that was, as “Aristotle”, and let me refer to this piece as book three of Ta Oikonomika – but with the caveats that it may not have been by the Stagirite, and its ancient source may not have even been one typically attributed to Aristole, although it was so attributed at some stage

When invited to consider the methodology of contemporary metaphysics, quite a number of procedures spring to mind as part of the metaphysician's toolkit. These include: eliciting and relying on intuitions; solving location problems and using “conceptual analysis”; inference to the best theory, both on internal metaphysical grounds and drawing from the theoretical reaches of the sciences; working on topics clearly close to, or even overlapping, those of other areas of inquiry using techniques of those other areas; achieving coherence with other theories developed with other aims; and employing deductive reasoning to yield surprising conclusions. Many of these techniques are associated with significant and growing literatures about their scope, epistemic justification, suitability to different metaphysical problems, and so on.

We discuss explanation of an earlier event by a later event, and argue that prima facie cases of backwards event explanation are ubiquitous. Some examples: (1) I am tidying my flat because my brother is coming to visit tomorrow. (2) The scarlet pimpernels are closing because it is about to rain. (3) The volcano is smoking because it is going to erupt soon. We then look at various ways people might attempt to explain away these prima facie cases by arguing that in each case the 'real' explanation is something else. We argue that none of the explaining-away strategies are successful, and so any plausible account of explanation should either make room for backwards explanation, or have a good story to tell about why it doesn't have to

In Metaphysics A, Aristotle offers some objections to Plato’s theory of Forms to the effect that Plato’s Forms would not be explanatory in the right way, and seems to suggest that they might even make the explanatory project worse. One interesting historical puzzle is whether Aristotle can avoid these same objections to his own theory of universals. The concerns Aristotle raises are, I think, cousins of contemporary concerns about the usefulness and explanatoriness of abstract objects, some of which have recently been receiving attention in the philosophy of mathematics. After discussing Aristotle’s objections and their contemporary cousins, the paper discusses some of the main available lines of response to these sorts of challenges, before concluding with an examination of whether these responses could assist Plato or Aristotle in responding to these challenges.