On several occasions, Kant posed a dichotomy or trichotomy concerning the possible ways to explain the existence of a thing, within or outside of a proper science. For instance, writing in connection with artifacts and organisms in the Critique of Judgment, he pondered:Now if one asks why a thing exists, the answer is either that its existence and its generation have no relation at all to a cause acting according to intentions, and in that case one always understands its origin to be in the mechanism of nature; or there is some intentional ground of its existence (as a contingent natural being).