Founder of a Metaphysics of Morals 303nomy, of dynamics, of mechanics, and of phenomenology. In his explica¬
tion, Kant followed the mathematical method, "if not with all strictness
... at least imitatively."^119 For this reason, the chapters are somewhat
tediously subdivided into explications (or perhaps better translated, "def¬
initions"), observations about them, propositions, principle(s), and proofs.
This structure makes it difficult to summarize the argument of the book.
In his first chapter, Kant offers explications or definitions of matter,
motion, rest, and composite motion, and he formulates the following prin¬
ciple: "Every motion as object of a possible experience can be viewed at will
either as a motion of a body in space that is at rest, or as rest of the body
and motion of the space in the opposite direction with equal velocity."^120
Kant deals with "phoronomy," that is, with matter conceived purely kine-
matically without regard to the causes of motion. Defining matter as "the
movable in space," he uses the occasion to differentiate between a "space
which is itself movable" that "is called material, or ... relative space," and
space "in which all motion must ultimately be thought... which... is called
pure, or also absolute, space."^121
In the second chapter, which is concerned with the metaphysical foun¬
dations of dynamics, that is, with forces as the cause of motion, Kant deals
with the concept of matter being guided by the categories of reality, nega¬
tion, and limitation. He first defines matter as "the movable in space inso¬
far as it fills space," explicating the notion of "filling a space" as resistance
to "everything movable that strives by its motion to press into a certain
space."^122 This gives rise to Proposition 1: "Matter fills a space, not by its
mere existence, but by a special moving force."^123 The six definitions and
seven propositions that follow spell out the consequences of this "meta¬
physical-dynamical" conception of matter. Thus he defines attractive and
repulsive forces, and finds that matter fills space by the repulsive force
(Proposition 2). He then argues that matter can be compressed to infinity,
but is impenetrable (Proposition 3). He is attacking Descartes, among
others, in Proposition 3. Descartes had argued that extension entails what
Kant calls "absolute impenetrability."^124 He then tries to show that matter
is infinitely divisible (Proposition 4), that the force of attraction is necessary
for the possibility of matter as well (Propositions 5 and 6), that attraction
is an immediate action of one material body upon another through empty
space (Proposition 7), and that there is an original attractive force that is
infinitely extended throughout the universe (Proposition 8).
Kant believed that he had succeeded in showing that everything real
in objects of the external senses that is not simply a spatial characteristic