[44] 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.