[Footnote 1:  The rational concept of the soul as a simple, independent intelligence does not signify an actual being, but only expresses certain principles of systematic unity in the explanation of psychical phenomena, viz., “To regard all determinations as existing in one subject, all powers, as far as possible, as derived from, one fundamental power, all change as belonging to the states of one and the same permanent being, and to represent all phenomena in space as totally distinct from acts of thought.”]

(2) The Antinomies of Rational Cosmology.  If in its endeavor to spin metaphysical knowledge concerning the nature of the spirit and the existence of the soul after death out of the concept of the thinking ego the reason falls into the snare of an ambiguous terminus medius, the difficulties which frustrate its attempts to use the Idea of the world in the extension of its knowledge a priori are of quite a different character.  Here the formal correctness of the method of inference is not open to attack.  It may be proved with absolute strictness (and in the apagogical or indirect form, from the impossibility of the contrary) that the world has a beginning in time, and also that it is limited in space; that every compound substance consists of simple parts; that, besides the causality according to the laws of nature, there is a causality through freedom, and that an absolutely necessary Being exists, either as a part of the world or as the cause of it.  But the contrary may be proved with equal stringency (and indirectly, as before):  The world is infinite in space and time; there is nothing simple in the world; there is no freedom, but everything in the world takes place entirely according to the laws of nature; and there exists no absolutely necessary Being either within the world or without it.  This is the famous doctrine of the conflict of the four cosmological theses and antitheses or of the Antinomy of Pure Reason, the discovery of which indubitably exercised a determining influence upon the whole course of the Kantian Critique of Reason, and which forms one of its poles.  The transcendental idealism, the distinction between phenomena and noumena, and the limitation of knowledge to phenomena, all receive significant confirmation from the Antithetic.  Without the critical idealism (that which is intuited in space and time, and known through the categories, is merely the phenomenon of things, whose “in itself” is unknowable), the antinomies would be insoluble.  How is reason to act in view of the conflict?  The grounds for the antitheses are just as conclusive as those for the theses; on neither side is there a preponderance which could decide the result.  Ought reason to agree with both parties or with neither?