Josh Parsons

(1973 - 2017)

The problem of imperative consequence consists in the fact that theses (i) through (iii) are inconsistent; but yet all three are attractive (for the reasons sketched above). A solution to the problem consists in the denial of one of the three theses; I describe solutions as belonging to type 1, type 2, or type 3, depending on which thesis they deny. For the purposes of this paper, I would like to focus on a certain variety of type 3 solution – a solution that offers a revised criterion of validity of a particular kind

This book is a survey, fortified by original material, of metaphysical theories of modality set in terms of possible worlds. Those theories include what Divers calls “genuine realism”, or “GR” — this is David Lewis’s “genuine modal realism” — and what Divers calls “actualist realism”, or “AR” — this seems to be the same as what Lewis called “ersatz modal realism”, which has also become widely know as “ersatzism”. Two important kinds of theory are not included: those that treat modality by means not involving possible worlds at all (for example, modalism, various kind of non-cognitivism, and Quinean eliminativism about modality); and those that, while treating modality by talking about possible worlds, go on to deny that there are any possible worlds in one way or another (for example, Rosen’s fictionalism, and Divers’ own agnosticism about possible worlds). These get a short discussion towards the end of the introductory part of the book (sections 2.4–2.6), and Divers is planning to write a companion volume covering them.

It’s now commonplace — since Korsgaard (1996) — in ethical theory to distinguish between two distinctions: on the one hand, the distinction between value an object has in virtue of its intrinsic properties vs. the value it has in virtue of all its properties, intrinsic or extrinsic; and on the other hand, the distinction between the value has an object as an end, vs. the value it has as a means to something else. I’ll call the former distinction the distinction between intrinsic and nonintrinsic value; the latter is between value as-an-end and instrumental value.

Here is a puzzle from the Stoic, Chrysippus: There was once a man called Dion, who was unfortunate enough to have his foot annihilated. Thereafter, he was known as Theon. Theon is identical to what was left over after Dion’s foot was removed. That is, Theon is that part of Dion that does not include his foot. If all this is true, then Theon is a proper part of Dion. That is, he is a part of Dion, but not identical to Dion. But if that’s right, then, surprisingly, Dion didn’t survive the loss of his foot.

This seems to me to be a metaphysically significant feature of CEM. If CEM is correct — if all its theorems are true, then metaphysicians have a choice to make in how we understand the mereological nature of the world. We may think of the mereological relation either as a relation of part to whole, or as a relation of overlap; for if we give a metaphysical theory about one, we thereby give a metaphysical theory about the other. We may choose which we think of as more metaphysically fundamental, for the they are interdefinable. However, if CEM is not correct, then perhaps we do not have this choice. Perhaps part-whole cannot be defined in terms of overlap; in which case we must choose part-whole as the metaphysical fundamental mereological relation (if any relation is)

I want to join Dummett in saying that the reality of the past (and, by analogy, the reality of the future) is an issue of realism versus anti-realism: (Dummett 1969) If you affirm the reality of the past, you are a realist about the past. If you deny the reality of the past, you are an anti-realist about the past. (And likewise, in each case, for the future). It makes sense to think of these issues by analogy with realism about the external world, unobservable objects, mathematical objects, universals, and so on. These are all properly described as ontological issues.

In my (2004), I argued that it is possible to drink any finite amount of alcohol without ever suffering a hangover by completing a certain kind of supertask. Assume that a drink causes drunkenness to ensue immediately and to last for a period proportional to the quantity of alcohol consumed; that a hangover begins immediately at the time the drunkenness ends and lasts for the same length of time as the drunkenness; and that at any time during which you are drunk you do not suffer any hangover you might have at that time. Starting at a time at which you are not drunk and not hung over, drink a half pint of beer. Wait until you are just about to get a hangover (30 minutes, say), and then drink a quarter pint. Wait until you are just about to get a hangover again, and then drink an eighth, and so on.... After an hour you have drunk a pint, and you do not have a hangover. Every hangover you incurred happened within the hour you spent drinking; but you were drunk that whole time, so you didn’t suffer the hangovers. It seems that the old drunkard’s method of a “hair of the dog” can be effective in completely avoiding a hangover.

The following quotation, from Frank Jackson, is the beginning of a typical exposition of the debate between those metaphysicians who believe in temporal parts, and those who do not: The dispute between three-dimensionalism and four-dimensionalism, or more precisely, that part of the dispute we will be concerned with, concerns what persistence, and correllatively, what change, comes to. Three-dimensionalism holds that an object exists at a time by being wholly present at that time, and, accordingly, that it persists if it is wholly present at more than one time. For short, it persists by enduring. Four-dimensionalism holds that an object exists at a time by having a temporal part at that time, and it persists if it has distinct temporal parts at more than one time. For short, it persists by perduring. In the light of these comments, some readers will perhaps find the question that forms the title of this paper a little puzzling. They may have learned to use the terms ‘fourdimensionalism’ ‘perdurantism’ and ‘belief in temporal parts’ interchangeably; or perhaps even to define one in terms of the other. Such a usage, however, is inapposite. We might imagine a Flatland-like world of two spatial dimensions and one temporal, whose philosophers are divided between a theory of persistence on which they persist by having temporal parts, and a theory on which they persist by being wholly located in each of several times. This is just the same issue we face, but at least the label ‘four-dimensionalism’ seems inapposite: the four-dimensionalist Flatlanders believe in only three dimensions!