Thisnesses and Suchnesses

A thisness is what the medievals called a hacceity, which is Latin for thisness. Objects may or may not have thisnesses, but if an objects has one, it is a "property" that the object has simply in virtue of being that very object, not in virtue of anything else. If, for example, it were possible to change "everything" about an object, it would still have its thisness, and, if an object has a thisness, and we can identify the thisness, we can use it to identify the object. (Though Quine wants nothing to do with thisnesses, one might put the point in the following Quinean way: if there are thisnesses, then the identity condition of any object is that it has the thisness it does.)

A suchness is a property in a more usual sense. When we describe an object, we do so by naming some of the objects suchnesses.

Adams is interested in the question (which he agrees isn't terribly clear) whether objects have thisnesses. He is aware of a raging debate (raging between Quine and Kripke) about whether objects can be rigidly designated. He thinks the debaters take that question to be closely related to his (roughly, he thinks, they think an object has a thisness if and only if it can rigidly designated), and he thinks they are wrong. That has, besides the narrow and incredibly technical question at hand, a larger implication: if he is right, then semantic ascent doesn't work.

Adams thinks the metaphysical question whether there are thisnesses is quite different from the semantical question whether there are rigid designators. Here is one version of one of his arguments: Leibniz thinks that there is no such thing as a thisness (a "metaphysical thisness"): an object is fully determined by the collection of all of its qualities, or suchnesses. (Leibniz thinks actual qualities, but Adams would be happy to allow possible qualities into the mixture as well.) Since that collection is infinite and likely involves qualities we can't even name, that fact that that is all there is to an object doesn't mean that a person can know what the object is in through knowing enough of its qualities. Thus, according to Adams, Leibniz thinks that, as a matter of fact, we humans may not be able to identify an object through its qualities, and we may therefore pick it out as nothing more than its being the object that it is. That is, according to Adams, according to Leibniz, there are "semantic thisnessess" that are not "metaphysical thisnesses" because they are not "metaphysically primitive." Thus, even if the facts of language require "semantic thisnesses," that does not show that there are "metaphysical thisnesses." That is the argument that the question of rigid designators, which Adams seems to concede is closely related to the question whether there are semantic thisnesses misses the boat if it is supposed to help in settling whether there are metaphysical thisnesses. Even if Leibniz is completely wrong, the argument shows that semantical and metaphysical thisnesses could be different, and so at the very least, an argument for metaphysical thisnesses based on an argument for semantical thisnesses needs to show that the semantical thisnesses require the metaphysical ones, or something like that, which, of course, anyone who indulges in semantic ascent misses, since metaphysical anything, and, in particular, metaphysical thisnesses drop out of the picture.

Your initial reaction might well be that if Adams is right, he has just turned his metaphysical question into one that we cannot approach, since the methods we have all concern semantical thisnesses. Adams thinks that the medievals had it right: the way to get at the problem is through considering whether indiscernibles are necessarily identical: if they are not, then there must be thisnesses, though, if they are, we don't get an answer.

So, can there be distinct indiscernibles? He mentions Black's world with two iron spheres and Hacking's criticism of it on behalf of Quineans.

-- ShaughanLavine - 13 Feb 2008