the critique of pure reason-第39节
按键盘上方向键 ← 或 → 可快速上下翻页,按键盘上的 Enter 键可回到本书目录页,按键盘上方向键 ↑ 可回到本页顶部!
————未阅读完?加入书签已便下次继续阅读!
2 3
Anticipations Analogies
of Perception of Experience
4
Postulates of
Empirical Thought
in general
These appellations I have chosen advisedly; in order that we might
not lose sight of the distinctions in respect of the evidence and
the employment of these principles。 It will; however; soon appear
that… a fact which concerns both the evidence of these principles; and
the a priori determination of phenomena… according to the categories
of quantity and quality (if we attend merely to the form of these);
the principles of these categories are distinguishable from those of
the two others; in as much as the former are possessed of an
intuitive; but the latter of a merely discursive; though in both
instances a complete; certitude。 I shall therefore call the former
mathematical; and the latter dynamical principles。* It must be
observed; however; that by these terms I mean just as little in the
one case the principles of mathematics as those of general
(physical) dynamics in the other。 I have here in view merely the
principles of the pure understanding; in their application to the
internal sense (without distinction of the representations given
therein); by means of which the sciences of mathematics and dynamics
become possible。 Accordingly; I have named these principles rather
with reference to their application than their content; and I shall
now proceed to consider them in the order in which they stand in the
table。
*All combination (conjunctio) is either composition (compositio)
or connection (nexus)。 The former is the synthesis of a manifold;
the parts of which do not necessarily belong to each other。 For
example; the two triangles into which a square is divided by a
diagonal; do not necessarily belong to each other; and of this kind is
the synthesis of the homogeneous in everything that can be
mathematically considered。 This synthesis can be divided into those of
aggregation and coalition; the former of which is applied to
extensive; the latter to intensive quantities。 The second sort of
combination (nexus) is the synthesis of a manifold; in so far as its
parts do belong necessarily to each other; for example; the accident
to a substance; or the effect to the cause。 Consequently it is a
synthesis of that which though heterogeneous; is represented as
connected a priori。 This combination… not an arbitrary one… I
entitle dynamical because it concerns the connection of the
existence of the manifold。 This; again; may be divided into the
physical synthesis; of the phenomena divided among each other; and the
metaphysical synthesis; or the connection of phenomena a priori in the
faculty of cognition。
1。 AXIOMS OF INTUITION。
The principle of these is: All Intuitions are Extensive
Quantities。
PROOF。
All phenomena contain; as regards their form; an intuition in
space and time; which lies a priori at the foundation of all without
exception。 Phenomena; therefore; cannot be apprehended; that is;
received into empirical consciousness otherwise than through the
synthesis of a manifold; through which the representations of a
determinate space or time are generated; that is to say; through the
composition of the homogeneous and the consciousness of the
synthetical unity of this manifold (homogeneous)。 Now the
consciousness of a homogeneous manifold in intuition; in so far as
thereby the representation of an object is rendered possible; is the
conception of a quantity (quanti)。 Consequently; even the perception
of an object as phenomenon is possible only through the same
synthetical unity of the manifold of the given sensuous intuition;
through which the unity of the composition of the homogeneous manifold
in the conception of a quantity is cogitated; that is to say; all
phenomena are quantities; and extensive quantities; because as
intuitions in space or time they must be represented by means of the
same synthesis through which space and time themselves are determined。
An extensive quantity I call that wherein the representation of
the parts renders possible (and therefore necessarily antecedes) the
representation of the whole。 I cannot represent to myself any line;
however small; without drawing it in thought; that is; without
generating from a point all its parts one after another; and in this
way alone producing this intuition。 Precisely the same is the case
with every; even the smallest; portion of time。 I cogitate therein
only the successive progress from one moment to another; and hence; by
means of the different portions of time and the addition of them; a
determinate quantity of time is produced。 As the pure intuition in all
phenomena is either time or space; so is every phenomenon in its
character of intuition an extensive quantity; inasmuch as it can
only be cognized in our apprehension by successive synthesis (from
part to part)。 All phenomena are; accordingly; to be considered as
aggregates; that is; as a collection of previously given parts;
which is not the case with every sort of quantities; but only with
those which are represented and apprehended by us as extensive。
On this successive synthesis of the productive imagination; in the
generation of figures; is founded the mathematics of extension; or
geometry; with its axioms; which express the conditions of sensuous
intuition a priori; under which alone the schema of a pure
conception of external intuition can exist; for example; 〃be tween two
points only one straight line is possible;〃 〃two straight lines cannot
enclose a space;〃 etc。 These are the axioms which properly relate only
to quantities (quanta) as such。
But; as regards the quantity of a thing (quantitas); that is to say;
the answer to the question: 〃How large is this or that object?〃
although; in respect to this question; we have various propositions
synthetical and immediately certain (indemonstrabilia); we have; in
the proper sense of the term; no axioms。 For example; the
propositions: 〃If equals be added to equals; the wholes are equal〃;
〃If equals be taken from equals; the remainders are equal〃; are
analytical; because I am immediately conscious of the identity of
the production of the one quantity with the production of the other;
whereas axioms must be a priori synthetical propositions。 On the other
hand; the self…evident propositions as to the relation of numbers; are
certainly synthetical but not universal; like those of geometry; and
for this reason cannot be called axioms; but numerical formulae。
That 7 + 5 = 12 is not an analytical proposition。 For neither in the
representation of seven; nor of five; nor of the composition of the
two numbers; do I cogitate the number twelve。 (Whether I cogitate
the number in the addition of both; is not at present the question;
for in the case of an analytical proposition; the only point is
whether I really cogitate the predicate in the representation of the
subject。) But although the proposition is synthetical; it is
nevertheless only a singular proposition。 In so far as regard is
here had merely to the synthesis of the homogeneous (the units); it
cannot take place except in one manner; although our use of these
numbers is afterwards general。 If I say: 〃A triangle can be
constructed with three lines; any two of which taken together are
greater than the third;〃 I exercise merely the pure function of the
productive imagination; which may draw the lines longer or shorter and
construct the angles at its pleasure。 On the contrary; the number
seven is possible only in one manner; and so is likewise the number
twelve; which results from the synthesis of seven and five。 Such
propositions; then; cannot be termed axioms (for in that case we
should have an infinity of these); but numerical formulae。
This transcendental principle of the mathematics of phenomena
greatly enlarges our a priori cognition。 For it is by this principle
alone that pure mathematics is rendered applicable in all its
precision to objects of experience; and without it the validity of
this application would not be so self…evident; on the contrary;
contradictions and confusions have often arisen on this very point。
Phenomena are not things in themselves。 Empirical intuition is
possible only through pure intuition (of space and time);
consequently; what geometry affirms of the latter; is indisputably
valid of the former。 All evasions; such as the statement that
objects of sense do not conform to the rules of construction in
space (for example; to the rule of the infinite divisibility of
lines or angles); must fall to the ground。 For; if these objections
hold good; we deny to space; and with