Our Critique would be an investigation utterly superfluous, if there existed a possibility of proving a priori, that all thinking beings are in themselves simple substances, as such, therefore, possess the inseparable attribute of personality, and are conscious of their existence apart from and unconnected with matter.For we should thus have taken a step beyond the world of sense, and have penetrated into the sphere of noumena; and in this case the right could not be denied us of extending our knowledge in this sphere, of establishing ourselves, and, under a favouring star, appropriating to ourselves possessions in it.For the proposition: "Every thinking being, as such, is simple substance," is an a priori synthetical proposition;because in the first place it goes beyond the conception which is the subject of it, and adds to the mere notion of a thinking being the mode of its existence, and in the second place annexes a predicate (that of simplicity) to the latter conception- a predicate which it could not have discovered in the sphere of experience.It would follow that a priori synthetical propositions are possible and legitimate, not only, as we have maintained, in relation to objects of possible experience, and as principles of the possibility of this experience itself, but are applicable to things in themselves- an inference which makes an end of the whole of this Critique, and obliges us to fall back on the old mode of metaphysical procedure.But indeed the danger is not so great, if we look a little closer into the question.
There lurks in the procedure of rational Psychology a paralogism, which is represented in the following syllogism:
That which cannot be cogitated otherwise than as subject, does not exist otherwise than as subject, and is therefore substance.
A thinking being, considered merely as such, cannot be cogitated otherwise than as subject.
Therefore it exists also as such, that is, as substance.
In the major we speak of a being that can be cogitated generally and in every relation, consequently as it may be given in intuition.But in the minor we speak of the same being only in so far as it regards itself as subject, relatively to thought and the unity of consciousness, but not in relation to intuition, by which it is presented as an object to thought.Thus the conclusion is here arrived at by a Sophisma figurae dictionis.**Thought is taken in the two premisses in two totally different senses.In the major it is considered as relating and applying to objects in general, consequently to objects of intuition also.In the minor, we understand it as relating merely to self-consciousness.In this sense, we do not cogitate an object, but merely the relation to the self-consciousness of the subject, as the form of thought.In the former premiss we speak of things which cannot be cogitated otherwise than as subjects.In the second, we do not speak of things, but of thought all objects being abstracted), in which the Ego is always the subject of consciousness.Hence the conclusion cannot be, "I cannot exist otherwise than as subject";but only "I can, in cogitating my existence, employ my Ego only as the subject of the judgement." But this is an identical proposition, and throws no light on the mode of my existence.
That this famous argument is a mere paralogism, will be plain to any one who will consider the general remark which precedes our exposition of the principles of the pure understanding, and the section on noumena.For it was there proved that the conception of a thing, which can exist per se- only as a subject and never as a predicate, possesses no objective reality; that is to say, we can never know whether there exists any object to correspond to the conception;consequently, the conception is nothing more than a conception, and from it we derive no proper knowledge.If this conception is to indicate by the term substance, an object that can be given, if it is to become a cognition, we must have at the foundation of the cognition a permanent intuition, as the indispensable condition of its objective reality.For through intuition alone can an object be given.
But in internal intuition there is nothing permanent, for the Ego is but the consciousness of my thought.If then, we appeal merely to thought, we cannot discover the necessary condition of the application of the conception of substance- that is, of a subject existing per se-to the subject as a thinking being.And thus the conception of the simple nature of substance, which is connected with the objective reality of this conception, is shown to be also invalid, and to be, in fact, nothing more than the logical qualitative unity of self-consciousness in thought; whilst we remain perfectly ignorant whether the subject is composite or not.
Refutation of the Argument of Mendelssohn for the Substantiality or Permanence of the Soul.