Our knowledge is both co-extensive with being, and opposed to it. Our knowledge is co-extensive inasmuch as we speak of “all” and “nothing”; “is” and “is not”; “possible” and “impossible”. There can be nothing outside of thought. At the same time, thought is opposed to being, because the first principle of our knowledge contains “not” and “impossible”, although being does not contain “not” and “impossible”. In other words “impossible” proves both the infinity of human thought, and its opposition to being.
If our knowledge were in no way opposed to being, it would contain all being simply, totally, and with no admixture of non- being: the “not” and “impossible”.