For if judgement finds the teleological nexus of causes and effects quite indispensable for the possibility of an object like this, be it only for the purpose of studying it under the guidance of experience, and if a ground involving relation to ends and adequate for external objects as phenomena altogether eludes us, so that we are compelled, although this ground lies in nature, to look for it in the supersensible substrate of nature, all possible insight into which is, however, cut off from us: it is absolutely impossible for us to obtain any explanation at the hand of nature itself to account for any synthesis displaying purposiveness.