Benedict de Spinoza, THE ETHICS
Page: 16

individual prefixed to Lemma iv.

*****Note--We thus see, how a composite individual may be
affected in many different ways, and preserve its nature
notwithstanding. Thus far we have conceived an individual as
composed of bodies only distinguished one from the other in
respect of motion and rest, speed and slowness; that is, of
bodies of the most simple character. If, however, we now
conceive another individual composed of several individuals of
diverse natures, we shall find that the number of ways in which
it can be affected, without losing its nature, will be greatly
multiplied. Each of its parts would consist of several bodies,
and therefore (by Lemma vi.) each part would admit, without
change to its nature, of quicker or slower motion, and would
consequently be able to transmit its motions more quickly or more
slowly to the remaining parts. If we further conceive a third
kind of individuals composed of individuals of this second kind,
we shall find that they may be affected in a still greater
number of ways without changing their actuality. We may easily
proceed thus to infinity, and conceive the whole of nature as
one individual, whose parts, that is, all bodies, vary in
infinite ways, without any change in the individual as a whole.
I should feel bound to explain and demonstrate this point at
more length, if I were writing a special treatise on body. But
I have already said that such is not my object; I have only
touched on the question, because it enables me to prove easily
that which I have in view.

POSTULATES I. The human body is composed of a number of
individual parts, of diverse nature, each one of which is in
itself extremely complex.

II. Of the individual parts composing the human body some are
fluid, some soft, some hard.

III. The individual parts composing the human body, and
consequently the human body itself, are affected in a variety of
ways by external bodies.

IV. The human body stands in need for its preservation of a
number of other bodies, by which it is continually, so to speak,
regenerated.

V. When the fluid part of the human body is determined by an