erstanding itself reduces all other predicates of matter to
this. The second and most valuable part of the work defines matter as the
movable, that which fills space by its moving force, and recognizes two
original forces, repulsive, expansive superficial force or force of
contact, by which a body resists the entrance of other bodies into its own
space, and attractive, penetrative force or the force which works at a
distance, in virtue of which all particles of matter attract one another.
In order to a determinate filling of space the co-operation of both
fundamental forces is required. In opposition to the mechanical theory of
the atomists, which explains forces from matter and makes them inhere in
it, Kant holds fast to the dynamical view which he had early adopted (cf.
p. 324), according to which forces are the primary factor and matter is
constituted by them.]

The outcome of the Analytic of Principles sounds bold enough. _The
understanding is the lawgiver of nature_: "It does not draw its laws _a
priori_ from nature, but prescribes them to it"; the principles of the pure
understanding are the most universal laws of nature, the empirical laws of
nature only particular determinations of these. All order and regularity
take their origin in the spirit, and are put into objects by this.
Universal and necessary knowledge remained inexplicable so long as it was
assumed that the understanding must conform itself to objects; it is at
once explained if, conversely, we make objects conform themselves to the
understanding. This is a reversal of philosophical opinion which may justly
be compared to the Copernican revolution in astronomy; it is just as
paradoxical as the latter, but just as incontestably true, and just as rich
in results. The sequel will show that this strangely sounding principle,
that things conform themselves to our representations and the laws of
nature are dependent on the understanding, is calculated to make us humble
rather than proud. Our understanding is lawgiver within the limits of its
knowledge, no doubt, but it knows only within the limits of its legislative
authority; nature, to which it dictates laws, is nothing but a totality of
phenomena; beyond the limits of the phenomenal, where its commands become
of no effect, its wishes also find no hearing.

In the second edition the Analytic of Principles contains as a supplement a
"Refutation of Idealism," which, in opposition to Descartes's position that