which is in itself and is conceived through itself. Because sub-
stances having different attributes have nothing in common
with one another, and because if two things have nothing in
common, one cannot be the cause of the other, then it is evi-
dent that all the entities of which humans have experience,
including themselves, must, because they all have extension
in common, constitute one substance. Although a human
being is also characterized by thought, which has nothing in
common with extension, since one is aware of one’s own ex-
tension, these two attributes cannot denote two substances
but must be instead two parallel manifestations of one and
the same substance. Spinoza thus insists that humans have
a clear and distinct idea of substance or God having at least
two parallel attributes. (In Ethics 1.11 he defines God as con-
sisting of infinite attributes, each one of which expresses eter-
nal and infinite essence, but some scholars believe that Spi-
noza is here using the term infinite as a synonym for all, and
that what he means to say in this proposition is that God ex-
ists in every possible basic way. Although he elsewhere hints
that there may be more than two attributes, he stops short
of saying that there are. Even more controversial is the ques-
tion whether the attributes are to be understood as subjective
or objective.) Although this conception of substance is ulti-
mately derived from empirical observation, it is not depen-
dent on any particular observation as such but follows from
the analysis of ideas and is therefore a product of the power
of the mind to think ideas and analyze their logical structure.
It is in this sense that knowledge of substance, or God, is a
priori, deriving essentially from an analysis of a given true
definition contained within the human mind. Spinoza desig-
nates knowledges of this kind as intuitive; he ranks it as the
highest form of knowledge humans have, above deductive
reasoning, which is mediated by the syllogistic process, and
imagination, which is based either on hearsay or random ex-
perience. For Spinoza, the only adequate or clear and distinct
ideas humans possess are those related to God, simple ideas,
and common notions, or axioms, and what is deduced from
them. Knowledge derived from syllogistic reasoning (which
yields universal knowledge) and intuitive knowledge (which
represents the power of the mind itself, on which syllogistic
reasoning ultimately rests) are necessarily true.
God is eternally in a state of self-modification, produc-
ing an infinite series of modes that are manifested under ei-
ther of his attributes. Under the attribute of extension, there
is the immediate infinite mode, motion and rest; and under
thought, the absolutely infinite intellect, or the idea of God.
Finally come the finite modes, or particular things. Sub-
stance with its attributes is called natura naturans, the cre-
ative or active divine power, whereas the entire modal sys-
tem, the system of what is created, is called natura naturata.
Spinoza’s God is thus not identical with the natural world
as such but only with the creative ground that encom-
passes it.
While others consider human actions and appetites as
virtues and vices to be bewailed or mocked, Spinoza consid-
ers them natural facts to be studied and understood. Vice is
impotence, whereas virtue is power. Individuals act when
anything is done of which they are the adequate cause; they
suffer when anything is done of which they are only the par-
tial cause. The first law of nature (as the Stoics had already
noted) is the impulse, or effort (conatus), by which each thing
endeavors to persevere in its own being. Humans do not de-
sire anything because they think it good, but humans ad-
judge a thing good because they desire it. Desire is activity
conducive to self-preservation; pleasure marks its increase,
pain its decrease. Spinoza offers a pioneering psychological
analysis of the ways through which the human imagination
acts and discusses in some detail the various laws of what he
calls the association and imitation of the emotions.Spinoza calls active emotions those which are related to
the mind insofar as it acts and of which an individual is the
adequate cause. Of these there are only two: desire, or the
effort of self-preservation in accordance with the dictates of
reason, and pleasure, or the enjoyment experienced from the
mind’s contemplation of itself whenever it conceives an ade-
quate or true idea. In the conflict of emotions, weaker emo-
tions are removed by stronger ones, as Plato had already indi-
cated in the Timaeus. Knowledge of good and evil can be a
determining factor only insofar as it is considered an emo-
tion—that is, a consciousness of pleasure and pain. Inas-
much as happiness consists in humans’ preservation of their
own beings and they act virtuously when effecting their self-
preservation in accordance with their full powers, humans
must seek to maximize their power to act, which means re-
moving their passive emotions to the greatest possible extent
and substituting for them active emotions.
Spinoza suggests various remedies for the passive emo-
tions, which he describes as mental diseases (already de-
scribed by the Stoics). Since a passive emotion is a confused
idea, the first remedy is to remove confusion and transform
it into a clear and distinct idea. Another remedy is to realize
that nothing happens except through the necessity of an infi-
nite causal series. Humans should also endeavor to expel the
many ghosts that haunt their minds by contemplating the
common properties of things. Indeed, the emotions them-
selves may become an object of contemplation. The sover-
eign remedy, however, is the love of God. The mind has the
capacity to cause all affections of the body to be related to
the idea of God; that is, to know them by intuitive knowl-
edge. Spinoza endeavors to demonstrate the immortality of
the human mind (stripped of sensation, memory, and imagi-
nation) but insists that even during a lifetime one can experi-
ence that state of immortality which he calls blessedness and
describes as union with, or love for, God. The intellectual
love of God, which arises from intuitive knowledge, is eternal
and is part of the infinite love with which God loves himself.
INFLUENCE ON LATER THOUGHT. Among the major philos-
ophers, Spinoza was the only one who did not found a
school. During the first hundred years after Spinoza’s death,
his name was connected principally with the Tractatus8684 SPINOZA, BARUCH