And how are we to determine that something that is presumed to be, at some place and time, is not—unless we can clearly distinguish in advance between Being and not-Being? How are we to make this decisive distinction unless we know just as decisively and definitely what is meant by what we are distinguishing here: not-Being and Being? How can beings always and in each case be beings for us unless we already understand “Being” and “not-Being”?

But we are constantly faced with beings. We distinguish between their Being-thus and Being-otherwise, we judge about Being and not-Being. We therefore know unambiguously what “Being” means. The claim that this word is empty and indefinite would then just be a superficial way of speaking and an error.

Such reflections put us in a supremely ambivalent position. We first determined that the word “Being” tells us nothing definite. We did not just talk ourselves into this; instead, we found out, and we still find now that “Being” has an evanescent, indefinite meaning. But on the other hand, our latest considerations convince us that we clearly and surely distinguish “Being” from not-Being.

In order to get our bearings here, we must pay attention to the following. Surely it can come into doubt whether at some place and time an individual being is or is not. We can deceive ourselves about whether, for example, the window over there, which is of course a being, is closed or is not. However, merely in order for such a thing to come into doubt at all, we must presume the definite distinction between Being and not-Being. Whether Being is distinct from not-Being is not something we doubt in this case.

The word “Being” is thus indefinite in its meaning, and nevertheless we understand it definitely. “Being” proves to be extremely definite and completely indefinite. According to the usual logic, we have here an obvious contradiction.