A distinction is commonly made between that which is immediately
cognized and that which is inferred or concluded. That in a figure
which is bounded by three straight lines there are three angles, is an
immediate cognition; but that these angles are together equal to two
right angles, is an inference or conclusion. Now, as we are constantly
employing this mode of thought and have thus become quite accustomed to
it, we no longer remark the above distinction, and, as in the case of
the so-called deceptions of sense, consider as immediately perceived,
what has really been inferred. In every reasoning or syllogism, there
is a fundamental proposition, afterwards a second drawn from it, and
finally the conclusion, which connects the truth in the first with the
truth in the second—and that infallibly. If the judgement concluded is
so contained in the first proposition that it can be deduced from it
without the meditation of a third notion, the conclusion is called
immediate (consequentia immediata); I prefer the term conclusion of the
understanding. But if, in addition to the fundamental cognition, a
second judgement is necessary for the production of the conclusion, it
is called a conclusion of the reason. In the proposition: All men are
mortal, are contained the propositions: Some men are mortal, Nothing
that is not mortal is a man, and these are therefore immediate
conclusions from the first. On the other hand, the proposition: all the
learned are mortal, is not contained in the main proposition (for the
conception of a learned man does not occur in it), and it can be
deduced from the main proposition only by means of a mediating
judgement.
In every syllogism I first cogitate a rule (the major) by means of the
understanding. In the next place I subsume a cognition under the
condition of the rule (and this is the minor) by means of the
judgement. And finally I determine my cognition by means of the
predicate of the rule (this is the conclusio), consequently, I
determine it à priori by means of the reason. The relations, therefore,
which the major proposition, as the rule, represents between a
cognition and its condition, constitute the different kinds of
syllogisms. These are just threefold—analogously with all judgements,
in so far as they differ in the mode of expressing the relation of a
cognition in the understanding—namely, categorical, hypothetical, and
disjunctive.