DESCARTES.
The beginner and founder of modern philosophy is _Descartes_. While he,
like the men of the transition epoch just noticed, broke loose entirely
from the previous philosophizing, and began his work wholly _de novo_,
yet he did not content himself, like Bacon, with merely bringing out a
new method, or like Boehme and his contemporaries among the Italians,
with affirming philosophical views without a methodical ground. He went
further than any of these, and making his standpoint one of universal
doubt, he affirms a new, positive, and pregnant philosophical principle,
from which he attempted logically to deduce the chief points of his
system. The character and novelty of his principle makes him the
beginner, and its inner fruitfulness the founder, of modern philosophy.
Rene Descartes (_Renatus Cartesius_) was born in 1596, at La Haye in
Torraine. Possessing an independent property, he volunteered as a
soldier in his twenty-first year, and served in the wars with the Dutch,
the Bavarians, and the Imperialists. After this he travelled a good
deal, and then abode a considerable time in Paris. In 1629 he left his
native land, and betook himself to Holland, that he might there,
undisturbed and unknown, devote himself to philosophy, and elaborate his
scientific ideas. He spent twenty years in Holland, enduring much
vexatious treatment from fanatical theologians, till in 1649 he accepted
an invitation from Queen Christina of Sweden, to visit Stockholm, where
he died in the following year.
The chief content of the Cartesian system may be seen condensed in the
following epitome.
1. If science would have any thing fixed and abiding, it must begin with
the primal ground of things; every presupposition which we may have
cherished from infancy must be abandoned; in a word, we must doubt at
every point to which the least uncertainty is attached. We must
therefore doubt not only the existence of the objects of sense, since
the senses so frequently deceive, but also the truths of mathematics and
geometry—for, however evident the proposition may appear that two and
three make five, or that the square has four sides, yet we cannot know
but what God may have designedly formed us for erroneous judgments. It
is therefore advisable to doubt every thing, in fact to deny every
thing, to posit every thing as false.
2. But though we posit every thing as false to which the slightest doubt
may be attached, yet we cannot deny one thing, viz., the truth that we,
who so think, do exist. But rather from the very fact that I posit every
thing as false, that I doubt every thing, is it manifest that I, the
doubter, exist. Hence the proposition: I think, therefore I am (_cogito
ergo sum_), is the first and most certain position which offers itself
to every one attempting to philosophize. Upon this the most certain of
all propositions, the certainty of all other knowledge depends. The
objection of _Gassendi_ that the truth of existence follows from any
other activity of man as well as from thinking, that I might just as
well say: I go to walk, therefore I exist,—has no weight; for, of all my
actions, I can be absolutely certain only of my thinking.
3. From the proposition I think, therefore, I am, the whole nature of
the mind may be determined. When we examine who we are who hold every
thing to be false that is distinct from ourselves, we see clearly that
neither extension nor figure, nor any thing which can be predicated of
body, but only thought, belongs to our nature. I am therefore only a
thinking being, _i. e._ mind, soul, intelligence, reason. Thought is my
substance. Mind can therefore be apprehended clearly and completely for
itself alone, without any of those attributes which belong to body. Its
conception contains nothing of that which belongs to the conception of
body. It is therefore impossible to apprehend it through any sensuous
representation, or to make an image of it: it apprehends itself only
through the pure intelligence.
4. From the proposition _cogito ergo sum_, follows still farther the
universal rule of all certainty. I am certain that I am a thinking
being, what now is involved in the fact that I am certain of any thing?
Whence comes this certainty? From no other source than the knowledge
that this first proposition contains a clear conception of that which I
affirm. I know of a certainty that I am, and I know any thing else only
when I know it as certainly as I know that I am. Hence I may regard it
as a universal rule, that every thing is true which I know clearly and
determinately.
5. This rule, however, is only a principle of certainty, not of
knowledge and of truth. We apply it therefore to our thoughts or ideas,
in order to discover what is objectively true. But our ideas are partly
innate, partly acquired, and partly self-originated. Among those of the
first class we find the idea of a God. The question arises, whence have
we this idea? Manifestly not from ourselves; this idea could only be
implanted within us by a being who has the fulness of all perfection in
himself, _i. e._ only by an actually existing God. If I ask now the
question, whence have I the faculty to conceive of a nature more perfect
than my own? the answer must ever come, that I have it only from him
whose nature is actually more perfect. All the attributes of God, the
more I contemplate them, show that their idea could not have originated
with myself alone. For though there might be in me the idea of substance
because I am a substance, yet I could not of myself have the idea of an
infinite substance, since I am finite; such an idea could only be given
me through a substance actually infinite. Moreover, we must not think
that the conception of the infinite is to be gained through abstraction
and negation, as we might gain darkness through the negation of light;
but I perceive, rather, that the infinite contains more reality than the
finite, and that, therefore, the conception of the infinite must be
correspondingly antecedent in me to that of the finite. Since then I
have a clear and determined idea of the infinite substance, and since
this has a greater objective reality than every other, so is there no
other which I have so little reason to doubt. But now since I am certain
that the idea of God has come to me from God himself, it only remains
for me to examine the way in which I have received it from God. I have
never derived it directly nor indirectly from the sense, for ideas
through the sense arise only by affecting the external organs of sense;
neither have I devised it, for I can neither add to it nor diminish it
in any respect,—it must, therefore, be innate as the idea of myself is
innate. Hence the first proof we can assign for the being of a God is
the fact that we find the idea of a God within us, and that we must have
a cause for its being. Again, the being of a God may be concluded from
my own imperfection, and especially from the knowledge of my
imperfection. For since I know that there is a perfection which is
wanting in me, it follows that there must exist a being who is more
perfect than I, on whom I depend and from whom I receive all I
possess.—But the best and most evident proof for the being of a God is,
in fine, that which is gained from the conception of a God. The mind
among all its different ideas singles out the chiefest of all, that of
the most perfect being, and perceives that this has not only the
possibility of existence, _i. e._ accidental existence like all other
ideas, but that it possesses necessary existence in itself. And as the
mind knows that in every triangle its three angles are equal to two
right angles, because this is involved in the very idea of a triangle,
so does the mind necessarily infer that necessary existence belongs to
the conception of the most perfect being, and that, therefore, the most
perfect being actually exists. No other idea which the mind finds within
itself contains necessary existence, but from the idea of the highest
being existence cannot be separated without contradiction. It is only
our prejudices which keep us from seeing this. Since we are accustomed
in every thing to separate its conception from its existence, and since
we often make ideas arbitrarily, it readily happens, that when we
contemplate the highest being we are in doubt whether its idea may not
be one also arbitrarily devised, or at least one in whose conception
existence does not lie.—This proof is essentially different from that of
Thomas (Anselm of Canterbury). His argument was as follows: “If we
understand what is indicated by the word GOD, it is all that can be
conceived of greatness; but now there is actually and in thought more
belonging to him than the word represents, and therefore God exists not
only in word (or representation), but in fact.” Here the defect in the
syllogism is manifest, for from the premise it could only be concluded
that God must therefore be _represented_ as existing in fact, while his
actual existence would not follow. My proof on the other hand is
this,—we may predicate of a thing what we clearly see belongs to its
true and changeless nature, or to its essence, or to its form. But now
after we had examined what God is, we found existence to belong to his
true and changeless nature, and therefore may we properly predicate
existence of God. Necessary existence is contained in the idea of the
most perfect being, not by a fiction of our understanding but because
existence belongs to his eternal and changeless nature.
6. The result just found—the existence of God—is of the highest
consequence. Before attaining this we were obliged to doubt every thing,
and give up even every certainty, for we did not know but that it
belonged to the nature of the human mind to err, but that God had
created us for error. But so soon as we look at the necessary attributes
of God in the innate idea of him, so soon as we know that he is true, it
would be a contradiction to suppose that he would deceive us, or that he
could have made us to err; for though an ability to deceive might prove
his skill, a willingness to deceive would only demonstrate his frailty.
Our reason, therefore, can never apprehend an object which would not be
true so far as the reason apprehended it, _i. e._ so far as it is
clearly known. For God might justly be styled a deceiver if he had given
us a reason so perverted as to hold the false for the true. And thus
every absolute doubt with which we began is dispelled. From the being of
God we derive every certainty. For every sure knowledge it is only
necessary that we have clearly known a thing, and are also certain of
the existence of a God, who would not deceive.
7. From the true idea of God follow the principles of a philosophy of
nature or the doctrine of the two substances. Substance is that which so
exists that it needs nothing else for its existence. In this (highest)
sense God is the only substance. God, as the infinite substance, has his
ground in himself, is the cause of himself. The two created substances,
on the other hand, the thinking and the corporeal substance, mind and
matter, are substances only in a broader sense of the word; they may be
apprehended under the common conception that they are things which need
only the co-operation of God for their existence. Each of these two
substances has an attribute which constitutes its nature and its
essence, and to which all its other determinations may be referred. The
attribute and essence of matter is extension, that of mind, thought. For
every thing else which can be predicated of body presupposes extension,
and is only a mode of extension, as every thing we can find in mind is
only a modification of thought. A substance to which thought immediately
belongs is called mind, and a substance, whose immediate substratum is
extension, is called body. Since thought and extension are distinct from
each other, and since mind cannot only be known without the attributes
of the body, but is in itself the negation of those attributes, we may
say that the essence of these substances is in their reciprocal
negation. Mind and body are wholly distinct, and have nothing in common.
8. We pass by the physics of Descartes, which has only a subordinate
philosophical interest, and notice next his views of anthropology. From
this dualistic relation between mind and matter, there follows a
dualistic relation between soul and body. If matter is essentially
extension, and mind essentially thought, and if the two have nothing in
common, then the union of soul and body can be conceived only as a
mechanical one. The body is to be regarded as an artistic automaton,
which God has made, as a statue or machine formed by God from the earth.
Within this body the soul dwells, closely but not internally connected
with it. The union of the two is only a powerful bringing of the two
together, since each is not only an independent factor, but is
essentially distinct from and even opposed to the other. The body by
itself is a machine fully prepared, in which nothing is changed by the
entrance of the thinking soul, except that through it certain motions
are secured: the wheel-work of the machine remains as it was. It is only
thought which distinguishes this machine from every other; hence,
therefore, brutes which are not self-conscious nor thinking, must be
ranked with all other machines. From this standpoint arose especially
the question concerning the seat of the soul. If body and soul are
independent substances, each essentially opposed to the other, they
cannot interpenetrate each other, but can touch only at one point when
they are powerfully brought together. This point where the soul has its
seat, is, according to Descartes, not the whole brain but the pineal
gland, a little kernel in the middle of the brain. The proof for this
claim, that the pineal gland is the only place where the soul
immediately exhibits its energy, is found in the circumstance that all
other parts of the brain are twofold, which should not be in an organ
where the soul has its seat, else objects would appear double. There is,
therefore, no other place in the body where impressions can be so well
united as in this gland. The pineal gland is, therefore, the chief seat
of the soul, and the place where all our thoughts are formed.
We have thus developed the fundamental thoughts of the Cartesian system,
and will now recapitulate in a few words the features characteristic of
its standpoint and historic position. Descartes was the founder of a new
epoch in philosophy, _first_, from his postulate of universal freedom
from all preconceptions. His protesting against every thing which is not
posited by the thought, against taking any thing for granted in respect
of the truth, has remained from that time onward the fundamental
principle of the new age. _Secondly._ Descartes has brought out the
principle of self-consciousness (the mind or the thinking substance is
regarded by him as an individual self, a particular Ego)—a new
principle, unknown in this view to the ancients. _Thirdly._ Descartes
has shown the opposition between being and thought, existence and
consciousness, and the mediation of this opposition, which has been the
problem of the whole modern philosophy, he first affirmed as the true
philosophical problem. But with these ideas, which make an epoch in the
history of philosophy, there are at the same time connected the defects
of the Cartesian philosophizing. _First._ Descartes gained the content
of his system, namely his three substances, empirically. True, the
system which begins with a protestation against all existence would seem
to take nothing for granted, but to derive every thing from the
thinking. But in fact this protesting is not thoroughly carried out.
That which seems to be cast aside is afterwards, when the principle of
certainty is gained, taken up again unchanged. And so it happens that
Descartes finds at hand not only the idea of God, but his two substances
as something _immediately given_. True, in order to reach them, he
abstracts every thing which lies immediately before him, but in the end
the two substances are seen as that which remains when all else is
abstracted. They are received _empirically_. The _second_ defect is,
that Descartes separates so wholly from each other the two sides of the
opposition between thought and being. He posits both as “substances,”
_i. e._ as powers, which reciprocally exclude and negate each other. The
essence of matter according to him consists _only_ in extension, _i. e._
in the pure being _extra se_ (_Aussersichsein_), and that of mind _only_
in thought, _i. e._ in the pure being _in se_ (_Insichsein_.) The two
stand over against each other as centrifugal and centripetal. But with
this apprehension of mind and matter, an inner mediation of the two is
an impossibility; there must be a powerful act of creation, there must
be the divine assistance in order that the two sides may ever come
together, and be united as they are in man. Nevertheless Descartes
demands and attempts such a mediation of the two sides. But the
impossibility of truly overcoming the dualism of his standpoint is the
_third_, and the chief defect of his system. In the proposition “I
think, therefore I am,” or “I am thinking,” the two sides, being and
thought, are indeed connected together, but only that they may become
fixed independently in respect of each other. If the question is asked,
how does the Ego stand related to the extended? the answer can only be:
by thinking, _i. e._ negatively, by excluding it. The idea of God,
therefore, is all that remains for the mediation of these two sides. The
two substances are created by God, and through the divine will may be
bound together; through the idea of God, the Ego attains the certainty
that the extended exists. God is therefore in a certain degree a _Deus
ex machina_, necessary in order to mediate the conflict of the Ego with
the extended. It is obvious how external such a mediation is.
This defect of the Cartesian system operated as an impelling motive to
those which succeeded.