SEP describes the thesis that metaphysics is impossible as follows:
Let us call the thesis that all metaphysical statements are meaningless “the strong form” of the thesis that metaphysics is impossible. (At one time, an enemy of metaphysics might have been content to say that all metaphysical statements were false. But this is obviously not a possible thesis if the denial of a metaphysical statement must itself be a metaphysical statement) And let us call the following statement the “weak form” of the thesis that metaphysics is impossible: metaphysical statements are meaningful, but human beings can never discover whether any metaphysical statement is true or false (or probable or improbable or warranted or unwarranted).
The strong thesis seems to refute itself, because any statement about the impossibility of metaphysical truth is itself a metaphysical truth.
What about the weak form of the thesis that metaphysics is impossible? Kant seems to echo this view, but I'm wondering of the current status of this thesis. SEP does not go into detail about this. Much of metaphysics apparently relies on general principles of rationality, such as simplicity, but it's not clear to me how we can apply these here. Of course, we can believe that such rationality is "good", in a general sense, but we really have no justification for it. While rationality may be justified in the sense that it is pragmatic for us in our present situation, I don't see how any principle of rationality can be used metaphysically.
So, what is the status of this thesis within the philosophical community? Have most metaphysicians accepted that they deal with purely (to borrow a term) possible worlds without any relation to the actual world, or do they assert that we can determine metaphysical truths in our present condition?