From Heather Dyke’s review of Katherine Hawley’s How Things Persist.

Stage theory combines elements of both its rivals. It shares perdurance theory’s commitment to a four-dimensional metaphysical framework but denies that theory’s account of predication and adopts instead something like endurance theory’s account of predication. It is not four-dimensional objects which satisfy predicates like ‘is a chair’ and which change by having some parts that are clean and some parts that are coffee-stained. Instead, it is the momentary stages that make up the four-dimensional objects which are chairs and which are clean or coffee-stained.

Let’s work backwards through this. The last sentence is entirely true. The penultimate sentence is I think true, though one might quibble with the claim that in stage theory stages are the things that change. (Do you Ted, if you’re reading this?) But how does the ante-penultimate sentence follow from those? In what way is the stage theory’s account of predication something like the endurance theory’s? In what way is a raven like a writing desk? In what way is a conversation on a Dublin street like a fight with a Trojan soldier? I’m puzzled.

I think what’s going on here is that both the endurance theory and the stage theory say that x is a chair is true just in case x itself is a chair, but the traditional perdurance theory is thought to say that this is true just in case x’s current temporal part is a chair. But this isn’t really comparing apples with apples. The perdurantist doesn’t reject the T-schema, she can say x satisfies is a chair, i.e. x is a chair is true, just in case x is a chair. She goes on to say something else about how x’s being a chair depends on features of x’s current temporal part, but she isn’t disagreeing yet. So is the difference that the stage theorist doesn’t go on to say anything like that. Er, not obviously. If you think that whether or not something is a chair depends on, say, the intent with which it was constructed, then when the stage theorist goes to say what x’s being a chair depends on, it will include (something like) a story about how x bears a counterpart relation to certain of its temporal counterparts, and how those parts were created for the intent of being sat upon, or something to this effect. In other words, temporal parts seem to come into the story about predication at more or less exactly the same time. I still think it’s a ravens and writing desks comparison.

In other news, the day’s philosophy papers blog entry is up. It’s much less exciting than yesterday, but there is still some stuff there of note.