This is just a short advertisement for those who got interested in Varzi’s problem of the many tenors, which I discussed in the Logos seminar this year. I found out that Thomas Sattig’s brand new book (on persistence, 3D, 4D and related issues) offers a very detailed discussion of the problem. (Actually, he discusses a more general problem, which he calls the problem of predicational overkill, that has Varzi’s problem about Tenor-Turnips as an instance). Varzi’s problem was this: given the alleged 4D principle that x is F at t iff x’s instantaneous temporal part at t is F simpliciter (plus some other assumptions), sentences like ‘Some tenor was a turnip’ come out true. Sattig discusses related problems for the alleged 4D principle. For instance, take a “uniqueness sentence”, like “Zoe and only Zoe is happy at t”. Prima facie, the 4D principle makes this sentence impossible. If Zoe is happy at t, her temporal part at t is also happy, and so are her many other temporal parts overlapping her temporal part at t. Sattig argues that even if this case can be handled by the 4D, things become more intractable when "cross-counting sentences" are considered (sentences like “Zoe and only Zoe is happy at t1 and sad at t2”). He offers different attempts to solve this problem on the 4D’s behalf, but concludes that none of them is satisfactory. Among these discarded 4D strategies, there is the appeal to quantifier domain restriction, which some of my audience at the Logos seminar seemed to favour prima facie. Another solution he considers and rejects draws on an idea that I had thought to be on the right track, namely to allow extended temporal parts to do the job that the 4D principle reserves for instantaneous temporal parts. I still have to think about his arguments against these views (I am not completely convinced).
On the other hand, the book also offers a very sophisticated and original framework for discussing the issues about persistence. Something that I found particularly interesting about this framework is that it makes clear the importance of linguistic considerations for assessing the views about persistence. That is to say, the framework justifies why the nature of persistence (or the “temporal dimension of reality”, more generally) should be studied in connection with the language about persistence (or “the temporal dimension of language”). If I got it right, the idea is this (very roughly and in my terminology rather than his): our ordinary conception of the world (as expressed in ordinary judgments about ordinary objects) is generally right and therefore supervenes on how the world is really like (as described by the metaphysician). Thus, any account about how the world is really like (3D, 4D, etc) must be such that the ordinary conception supervenes on it. Moreover, this supervenience cannot be taken as a large-scale brute fact. Rather, is must be possible to sate the facts about supervenience by means of specific bridge principles like the problematic 4D principle stated above (or more sophisticated versions of this). Thus, the correct view about the nature of persistence must be compatible with some “analysis” of the ordinary facts of persistence in terms of what persistence really is. Failure at offering such analyses (because of predicational overkill, etc) is a decisive reason against the view (or at least, it has much more weight than it would have under different assumptions). I like this view about methodology, but I suspect that most people working on the metaphysics of persistence will find it controversial. (Though I think they should not). I hope we will be discussing and clarifying these methodological issues in our up-coming e-reading group on metaontology.