I.
Of Logic in General.
OUR knowledge springs from two main sources in the mind, first of
which is the faculty or power of receiving representations
(receptivity for impressions); the second is the power of cognizing by
means of these representations (spontaneity in the production of
conceptions). Through the first an object is given to us; through
the second, it is, in relation to the representation (which is a
mere determination of the mind), thought. Intuition and conceptions
constitute, therefore, the elements of all our knowledge, so that
neither conceptions without an intuition in some way corresponding
to them, nor intuition without conceptions, can afford us a cognition.
Both are either pure or empirical. They are. empirical, when sensation
(which presupposes the actual presence of the object) is contained
in them; and pure, when no sensation is mixed with the representation.
Sensations we may call the matter of sensuous cognition. Pure
intuition consequently contains merely the form under which
something is intuited, and pure conception only the form of the
thought of an object. Only pure intuitions and pure conceptions are
possible a priori; the empirical only a posteriori.
We apply the term sensibility to the receptivity of the mind for
impressions, in so far as it is in some way affected; and, on the
other hand, we call the faculty of spontaneously producing
representations, or the spontaneity of cognition, understanding. Our
nature is so constituted that intuition with us never can be other
than sensuous, that is, it contains
only the mode in which we are
affected by objects. On the other hand, the faculty of thinking the
object of sensuous intuition is the understanding. Neither of these
faculties has a preference over the other. Without the sensuous
faculty no object would be given to us, and without the
understanding no object would be thought. Thoughts without content are
void; intuitions without conceptions, blind. Hence it is as
necessary for the mind to make its conceptions sensuous (that is, to
join to them the object in intuition), as to make its intuitions
intelligible (that is, to bring them under conceptions). Neither of
these faculties can exchange its proper function. Understanding cannot
intuite, and the sensuous faculty cannot think. in no other way than
from the united operation of both, can knowledge arise. But no one
ought, on this account, to overlook the difference of the elements
contributed by each; we have rather great reason carefully to separate
and distinguish them. We therefore distinguish the science of the laws
of sensibility, that is, æsthetic, from the science of the laws of
the understanding, that is, logic.
Now, logic in its turn may be considered as twofold— namely, as
logic of the general [universal],* or of the particular
use of the understanding.
The first contains the absolutely necessary laws of thought, without
which no use whatsoever of the understanding is possible, and gives
laws therefore to the understanding, without regard to the
difference of objects on which it may be employed. The logic of the
particular use of the understanding contains the laws of correct
thinking upon a particular class of objects. The former may be
called elemental logic— the latter, the organon of this or that
particular science. The latter is for the most part employed in the
schools, as a propædeutic to the sciences, although, indeed,
according to the course of human reason, it is the last thing we
arrive at, when the science has been already matured, and needs only
the finishing touches towards its correction and completion; for our
knowledge of the objects of our attempted science must be tolerably
extensive and complete before we can indicate the laws by which a
science of these objects can be established.
[_]
* Logic is nothing but the science of the laws of thought, as thought. It concerns itself only with the form
of thought, and takes no cognizance of the matter — that is, of the infinitude of the objects to which thought is applied.
Now Kant was wrong, when he divides logic into logic of the general and of the particular use of the understanding.
He says the logic of the particular use of the understanding contains the laws of right thinking upon any particular set of objects.
This sort of logic he calls the organon of this or that science. It is difficult to discover what he means by his
logic of the particular use of the understanding. From his description, we are left in doubt whether he means by this logic
induction, that is, the organon of science in general, or the laws which regulate the objects, a science of which he seeks to establish. —
In either case, the application of the term logic is inadmissible. To regard logic as the organon of science, is
absurd, as indeed Kant himself afterwards shows (p.51). It knows nothing of this or that object. That matter
employed in syllogisms is used for the sake of example only; all forms of syllogisms might be expressed in signs.
Logicians have never been able clearly to see this. They have never been able clearly to define the extent of their science,
to know, in fact, what their science really treated of. They have never seen that it has to do only with the
formal, and never with the material in thought. The science has broken down its proper barriers to let in contributions
from metaphysics, psychology, &c. It is common enough, for example, to say that Bacon's Novum Organum
entirely superseded the Organon of Aristotle. But the one states the laws under which a knowledge of objects
is possible; the other the subjective laws of thought. The spheres of the two are utterly distinct.
Kant very properly states that pure logic is alone properly science. Strictly speaking, applied logic cannot be a work
of general logic. It is more correctly applied psychology; — psychology treating in a practical manner of the conditions under which
thought is employed.
It may be noted here, that what Kant calls Transcendental Logic is properly not logic at all, but a work
of metaphysics. For his Categories contain matter — as regards thought at least. Take, for example, the category
of Existence. These categories, no doubt, are the forms of the matter given to us by experience. They are, according
to Kant, not derived from experience, but purely a priori. But logic is concerned exclusively about the form
of thought, and has nothing to do with this or that conception, whether a priori or a posteriori.
See Sir William Hamilton's Edition of Reid's Works, passim. It is to Sir William Hamilton, one of the
greatest logicians, perhaps the greatest, since Aristotle, and certainly one of the acutest thinkers of
any time, that the Translator is indebted for the above view of the subject of logic. — Tr.
General logic is again either pure or applied. In the former, we
abstract all the empirical conditions under which the understanding is
exercised; for example, the influence of the senses, the play of the
fantasy or imagination, the laws of the memory, the force of habit, of
inclination, &c., consequently also, the sources of prejudice— in a
word, we abstract all causes from which particular cognitions arise,
because these causes regard the understanding under certain
circumstances
of its application, and, to the knowledge of them
experience is required. Pure general logic has to do, therefore,
merely with pure
a priori principles, and is a canon of
understanding and reason, but only in respect of the formal part of
their use, be the content what it may, empirical or transcendental.
General logic is called applied, when it is directed to the laws of
the use of the understanding, under the subjective empirical
conditions which psychology teaches us. It has therefore empirical
principles, although, at the same time, it is in so far general,
that it applies to the exercise of the understanding, without regard
to the difference of objects. On this account, moreover, it is neither
a canon of the understanding in general, nor an organon of a
particular science, but merely a cathartic of the human understanding.
In general logic, therefore, that part which constitutes pure
logic must be carefully distinguished from that which constitutes
applied (though still general) logic. The former alone is properly
science, although short and dry, as the methodical exposition of an
elemental doctrine of the understanding ought to be. In this,
therefore, logicians must always bear in mind two rules:
1. As general logic, it makes abstraction of all content of the
cognition of the understanding, and of the difference of objects,
and has to do with nothing but the mere form of thought.
2. As pure logic, it has no empirical principles, and consequently
draws nothing (contrary to the common persuasion) from psychology,
which therefore has no influence on the canon of the understanding. It
is a demonstrated doctrine, and everything in it must be certain
completely a priori.
What I called applied logic (contrary to the common acceptation of
this term, according to which it should contain certain exercises
for the scholar, for which pure logic gives the rules), is a
representation of the understanding, and of the rules of its necessary
employment in concreto, that is to say, under the accidental
conditions of the subject, which may either hinder or promote this
employment, and which are all given only empirically. Thus applied
logic treats of attention, its impediments and consequences, of the
origin of error, of the state of doubt, hesitation, conviction,
&c., and to it is related pure general logic in the same way that
pure morality, which contains only the necessary moral laws of a
free will, is related to practical ethics, which considers these
laws under all the impediments of feelings, inclinations, and passions
to which men are more or less subjected, and which never can furnish
us with a true and demonstrated science, because it, as well as
applied logic, requires empirical and psychological principles.
