the impossible is evident...

I know that I exist, and nevertheless I am uncertain whether there is any ‘body’ in the nature of things. Therefore I am not a body. This argument is weak, unless it can be shown that extension in itself fully establishes substance. For even if this is assumed, it is certainly obvious that thought cannot originate from that substance; but this is not yet shown. And so we know this at least, that thought is not a mode of extension, but we do not know whether it cannot be a mode of substance, of which extension itself is a mode. [But it seems not to be so, because two different modes must be resolved into something common] For evidently extension and extended matter itself are different in body.

Therefore this is the true method of proving the distinction between mind and body: because it is impossible for us to ever know with certainty whether body exists. However I call body everything that is like those things that we perceive. But that this is impossible is evident, because it is impossible for us to be able to be made certain about the existence of bodies [except through a priori reasoning, from understanding the nature of God], or it cannot ever be proved by philosophical reasoning that bodies are not appearance or substances.

Gottfried Wilhelm Liebniz, The Distinction of Mind and Body, [Gr p511] [A VI iv p1368]

or the possible is evident...?