We have to ask ourselves whether, in any sense at all, there is such a thing as matter…It we cannot be sure of the independent existence of objects, we shall be left alone in a desert–it may be that the whole outer world is nothing but a dream, and that we alone exist. ..there is no logical impossibility in the supposition that the whole of life is a dream, in which we ourselves create all the objects that come before us. But although this is not logically impossible, there is no reason whatever to suppose that it is true; and is no reason whatever to suppose that it is true.
Bertrand Russell