Wittgenstein repeatedly criticised the idea of certain 'shadowy beings' which we believe to be necessary to relate two radically different things which apparently cannot be put directly in contact with each other, like thought and what it represents, sentence and what verifies it, desire and what realizes it, expectation and what satisfies it, etc. Wittgenstein tried to show that we are brought no nearer to the goal by the interposition of intermediary entities of that kind. In the case of a declarative sentence, the shadowy being must be a possibility which is expressed by the sentence and can be or not be realized. If the sentence is true, the possibility is supplanted by the corresponding fact; and if it is false, the only reality we have is so to speak the shadow, the possibility itself. One of the most fundamental theses of Wittgenstein's philosophy is that all possibility (at least "logical" or "grammatical" possibility, as he calls it) must be contained in language, and not between language and reality, in and intermediary realm of possibilities, and that it is all of the same kind and on the same level. To say that something is possible is simply to say that an expression has sense; and to say that it is impossible is not to say that the expression represents an impossible sense, as if we had first to consider a possible sense and then to exclude it as unreal or absurd, but simply that it has no use and does not belong to language. An important consequence of that is that, for Wittgenstein, there are no degrees of impossibility, no impossibilities that could be deeper and more radical than others. We cannot distinguish between a nonsense which makes (or at least could make) sense and a nonsense which does not. As Wittgenstein says, "what we exclude has no semblance of sense", it is not thinkable and does not have to be thought in some way in order to be excluded. What we exclude is always a use and not, so to speak, a possibility which turns out to be impossible.