Every one of my thoughts and judgments is based on the presupposition "I think." "I" is the subject and the thoughts are the predicates. Yet I should not confuse the ever-present "logical subject" of my every thought with a permanent, immortal, "real substance" (soul). The logical subject is a mere idea, not a real substance. Unlike Descartes who believes that the soul may be known directly through reason, Kant asserts that no such thing is possible. Descartes declares "cogito ergo sum" but Kant denies that any knowledge of "I" may be possible. "I" is only the background of the field of apperception and as such lacks the experience of direct intuition that would make self-knowledge possible. This implies that the self in itself could never be known. Like Hume, Kant rejects knowledge of the "I" as substance. For Kant, the "I" that is taken to be the soul is purely logical and involves no intuitions. The "I" is the result of the "a priori" consciousness continuum not of direct intuition "a posteriori". It is apperception as the principle of unity in the consciousness continuum that dictates the presence of "I" as a singular logical subject of all the representations of a single consciousness. Although "I" seems to refer to the same "I" all the time, it is not really a permanent feature but only the logical characteristic of a unified consciousness.