Richard Marshall interviews Markus Gabriel in 3:AM Magazine:
3:AM: Let’s start with your arguments about ontology. You argue that the world doesn’t exist and you want to be very clear that this isn’t what Kant, Heidegger or Gadamer might claim and then smuggle in a way round the claim – cheating! So can you first outline what philosophical position you are disagreeing with with your ‘real predicate’ argument? Metaphysics of a certain stripe collapses according to your idea doesn’t it?
MG: I agree with certain versions of the famous Kantian line of thought according to which existence is not what I call a proper property. In the first step of the overall argument, by a “proper property” I mean a property reference to which puts one in a position to distinguish an object in the world from other objects in the world. Existence certainly is not a property that divides the world up into two realms: that of the existing things on the one hand and that of the non-existing things (things lacking the feature of existence) on the other hand. That would be a weird world-picture.
Against this background, Kant has argued that existence is world-containment, that is, the world’s property to contain spatiotemporal individuals. On this construal, existence is precisely not a proper property of individuals. To assert that some object x exists is to say something about the world, namely that x is to be found in the world. However, this immediately raises the question whether the world itself can exist on this model? Is the world contained by the world? What exactly is the relation of containment supposed to be? Is the world some kind of set or a mereological whole? Would it even make sense to say that the world is a spatiotemporal individual located within the world and to be met with in it? What kind of totality is the world? All of Kant’s answers hinge on his notion of the world as the “field of possible experience” (CPR, A 227/B 280f.).
This creates all sorts of problems. Yet, what is right about his view is that to exist is a property of a field or a domain and not an ordinary discriminatory property of objects we encounter within the domain. As I read him, Kant distinguished between questions concerning the existence of individuals (which he takes to be a function mapping individuals onto the field of possible experience) and questions concerning the world itself. The latter, metaphysical questions, for him, are famously unanswerable.
If this is right, the question is what we mean when in metaphysics we search for the furniture of reality or the fundamental structure of the world. If “the world” is explicitly or implicitly modeled along the lines of a huge spatio-temporal container inhabited by the totality of individuals, this creates the problem that it is entirely unclear in what sense such a container is supposed to exist.
More here.