DESCARTES.
The long conflict with Scholasticism, which had been carried on with ever
increasing energy and ever sharper weapons, was brought by Descartes to a
victorious close. The new movement, long desired, long sought, and prepared
for from many directions, at length appears, ready and well-established.
Descartes accomplishes everything needful with the sure simplicity of
genius. He furnishes philosophy with a settled point of departure in
self-consciousness, offers her a method sure to succeed in deduction from
clear and distinct conceptions, and assigns her the mechanical explanation
of nature as her most imperative and fruitful mission.
René Descartes was born at La Haye in Touraine, in 1596, and died at
Stockholm in 1650. Of the studies taught in the Jesuit school at La Flèche,
mathematics alone was able to satisfy his craving for clear and certain
knowledge. The years 1613-17 he spent in Paris; then he enlisted in the
military service of the Netherlands, and, in 1619, in that of Bavaria.
While in winter quarters at Neuburg, he vowed a pilgrimage to Loretto if
the Virgin would show him a way of escape from his tormenting doubts; and
made the saving discovery of the "foundations of a wonderful science."
At the end of four years this vow was fulfilled. On his return to Paris
(1625), he was besought by his learned friends to give to the world his
epoch-making ideas. Though, to escape the distractions of society, he kept
his residence secret, as he had done during his first stay in Paris, and
frequently changed it, he was still unable to secure the complete privacy
and leisure for scientific work which he desired. Therefore he went to
Holland in 1629, and spent twenty years of quiet productivity in Amsterdam,
Franecker, Utrecht, Leeuwarden, Egmond, Harderwijk, Leyden, the palace of
Endegeest, and five other places. His work here was interrupted only by
a few journeys, but much disturbed in its later years by annoying
controversies with the theologian Gisbert Voëtius of Utrecht, with Regius,
a pupil who had deserted him, and with professors from Leyden. His
correspondence with his French friends was conducted through Père Mersenne.
In 1649 he yielded to pressing invitations from Queen Christina of Sweden
and removed to Stockholm. There his weak constitution was not adequate to
the severity of the climate, and death overtook him within a few months.
The two decades of retirement in the Netherlands were Descartes's
productive period. His motive in developing and writing out his thoughts
was, essentially, the desire not to disappoint the widely spread belief
that he was in possession of a philosophy more certain than the common one.
The work entitled _Le Monde_, begun in 1630 and almost completed, remained
unprinted, as the condemnation of Galileo (1632) frightened our philosopher
from publication; fragments of it only, and a brief summary, appeared
after the author's death. The chief works, the _Discourse on Method_, the
_Meditations on the First Philosophy_, and the _Principles of Philosophy_
appeared between 1637 and 1644,--the _Discours de la Méthode_ in 1637,
together with three dissertations (the "Dioptrics," the "Meteors," and the
"Geometry"), under the common title, _Essais Philosophiques_. To the (six)
_Meditationes de Prima Philosophia_, published in 1641, and dedicated to
the Paris Sorbonne, are appended the objections of various savants to whom
the work had been communicated in manuscript, together with Descartes's
rejoinders. He himself considered the criticisms of Arnauld, printed fourth
in order, as the most important. The Third Objections are from Hobbes, the
Fifth from Gassendi, the First, which were also the first received, from
the theologian Caterus of Antwerp, while the Second and Sixth, collected by
Mersenne, are from various theologians and mathematicians. In the second
edition there were added, further, the Seventh Objections, by the Jesuit
Bourdin, and the Replies of the author thereto. The four books of the
_Principia Philosophiae_, published in 1644 and dedicated to Elizabeth,
Countess Palatine, give a systematic presentation of the new philosophy.
The _Discourse on Method_ appeared, 1644, in a Latin translation, the
_Meditations_ and the _Principles_ in French, in 1647. The _Treatise on the
Passions_ was published in 1650; the _Letters_, 1657-67, in French, 1668,
in Latin. The _Opera Postuma_, 1701, beside the _Compendium of Music_
(written in 1618) and other portions of his posthumous writings, contain
the "Rules for the Direction of the Mind," supposed to have been written in
1629, and the "Search for Truth by the Light of Nature." The complete works
have been often published, both in Latin and in French. The eleven volume
edition of Cousin appeared in 1824-26.[1]
[Footnote 1: Of the many treatises on the philosophy of Descartes those of
C. Schaarschmidt (_Descartes und Spinoza_, 1850) and J.H. Löwe, 1855, may
be mentioned. Further, M. Heinze has discussed _Die Sittenlehre des
Descartes_, 1872; Ed. Grimm, _Descartes' Lehre von den angeborenen
Ideen_, 1873; G. Glogau, _Darlegung und Kritik des Grundgedankens der
Cartesianisch. Metaphysik (Zeitschrift für Philosophie_, vol. lxxiii. p.
209 _seq_.), 1878; Paul Natorp, _Descartes' Erkenntnisstheorie_, 1882;
and Kas. Twardowski, _Idee und Perception_ in Descartes, 1892. In French,
Francisque Bouillier (_Histoire de la Philosophie Cartésienne_, 1854) and
E. Saisset (_Précurseurs et Disciples de Descartes_, 1862) have written
on Cartesianism. [The _Method, Meditations, and Selections from the
Principles_ have been translated into English by John Veitch, 5th ed.,
1879, and others since; and H.A.P. Torrey has published _The Philosophy
of Descartes in Extracts from his Writings_, 1892 (Sneath's Modern
Philosophers). The English reader may be referred, also, to Mahaffy's
_Descartes_, 1880, in Blackwood's Philosophical Classics; to the article
"Cartesianism," _Encyclopedia Britannica_, 9th ed., vol. v., by Edward
Caird; and, for a complete discussion, to the English translation of
Fischer's _Descartes and his School_' by J.P. Gordy, 1887.--TR.]]
We begin our discussion with Descartes's noëtical and metaphysical
principles, and then take up in order his doctrine of nature and of man.
%1. The Principles%.
That which passes nowadays for science, and is taught as such in the
schools, is nothing but a mass of disconnected, uncertain, and often
contradictory opinions. A principle of unity and certainty is entirely
lacking. If anything permanent and irrefutable is to be accomplished in
science, everything hitherto considered true must be thoroughly demolished
and built up anew. For we come into the world as children and we form
judgments of things, or repeat them after others, before we have come into
the full possession of our intellectual powers; so that it is no wonder
that we are filled with a multitude of prejudices, from which we can
thoroughly escape only by considering everything doubtful which shows the
least sign of uncertainty. Let us renounce, therefore, all our old views,
in order later to accept better ones in their stead; or, perchance, to
take the former up again after they shall have stood the test of rational
criticism. The recognized precaution, never to put complete confidence in
that which has once deceived us, holds of our relation to the senses as
elsewhere. It is certain that they sometimes deceive us--perhaps they do so
always. Again, we dream every day of things which nowhere exist, and there
is no certain criterion by which to distinguish our dreams from our waking
moments,--what guarantee have we, then, that we are not always dreaming?
Therefore, our doubt must first of all be directed to the existence of
sense-objects. Nay, even mathematics must be suspected in spite of the
apparent certainty of its axioms and demonstrations, since controversy
and error are found in it also.
I doubt or deny, then, that the world is what it appears to be, that there
is a God, that external objects exist, that I have a body, that twice
two are four. One thing, however, it is impossible for me to bring into
question, namely, that I myself, who exercise this doubting function,
exist. There is one single point at which doubt is forced to halt--at the
doubter, at the self-existence of the thinker. I can doubt everything
except that I doubt, and that, in doubting, I am. Even if a superior being
sought to deceive me in all my thinking, he could not succeed unless I
existed, he could not cause me not to exist so long as I thought. To be
deceived means to think falsely; but that something is thought, no matter
what it be, is no deception. It might be true, indeed, that nothing at all
existed; but then there would be no one to conceive this non-existence.
Granted that everything may be a mistake; yet the being mistaken, the
thinking is not a mistake. Everything is denied, but the denier remains.
The whole content of consciousness is destroyed; consciousness itself, the
doubting activity, the being of the thinker, is indestructible. _Cogitatio
sola a me divelli nequit_. Thus the settled point of departure required for
knowledge is found in the _self-certitude of the thinking ego_. From the
fact that I doubt, _i.e._, think, it follows that I, the doubter, the
thinker, am. _Cogito, ergo sum_ is the first and most certain of all
truths.
The principle, "I think, therefore I am," is not to be considered a
deduction from the major premise, "Whatever thinks exists." It is rather
true that this general proposition is derived from the particular and
earlier one. I must first realize in my own experience that, as thinking, I
exist, before I can reach the general conclusion that thought and existence
are inseparable. This fundamental truth is thus not a syllogism, but a
not further deducible, self-evident, immediate cognition, a pure
intuition--_sum cogitans_. Now, if my existence is revealed by my activity
of thought, if my thought is my being, and the converse, if in me thought
and existence are identical, then I am a being whose essence consists in
thinking. I am a spirit, an ego, a rational soul. My existence follows only
from my thinking, not from any chance action. _Ambulo ergo sum_ would not
be valid, but _mihi videor_ or _puto me ambulare, ergo sum_. If I believe
I am walking, I may undoubtedly be deceived concerning the outward action
(as, for instance, in dreams), but never concerning my inward belief.
_Cogitatio_ includes all the conscious activities of the mind, volition,
emotion, and sensation, as well as representation and cognition; they are
all _modi cogitandi_. The existence of the mind is therefore the most
certain of all things. We know the soul better than the body. It is for
the present the only certainty, and every other is dependent on this, the
highest of all.
What, then, is the peculiarity of this first and most certain knowledge
which renders it self-evident and independent of all proof, which makes
us absolutely unable to doubt it? Its entire clearness and distinctness.
Accordingly, I may conclude that everything which I perceive as clearly and
distinctly as the _cogito ergo sum_ is also true, and I reach this general
rule, _omne est verum, quod clare et distincte percipio_. So far, then, we
have gained three things: a challenge; to be inscribed over the portals
of certified knowledge, _de omnibus dubitandum_; a basal truth, _sum
cogitans_; a criterion of truth, _clara et distinct a perceptio_.
The doubt of Descartes is not the expression of a resigned spirit which
renounces the unattainable; it is precept, not doctrine, the starting point
of philosophy, not its conclusion, a methodological instrument in the hand
of a strong and confident longing for truth, which makes use of doubt to
find the indubitable. It is not aimed at the possibility of attaining
knowledge, but at the opinion that it has already been attained, at the
credulity of the age, at its excessive tendency toward historical and
poly-historical study, which confuses the acquisition and handing down of
information with knowledge of the truth. That knowledge alone is certain
which is self-attained and self-tested--and this cannot be learned
or handed down; it can only be rediscovered through examination and
experience. Instead of taking one's own unsupported conjectures or the
opinions of others as a guide, the secret of the search for truth is to
become independent and of age, to think for one's self; and the only remedy
against the dangers of self-deception and the ease of repetition is to be
found in doubting everything hitherto considered true. This is the meaning
of the Cartesian doubt, which is more comprehensive and more thorough
than the Baconian. Descartes disputed only the certitude of the knowledge
previously attained, not the possibility of knowledge--for of the latter no
man is more firmly convinced than he. He is a rationalist, not a skeptic.
The intellect is assured against error just as soon as, freed from
hindrances, it remains true to itself, as it puts forth all its powers and
lets nothing pass for truth which is not clearly and distinctly known.
Descartes demands the same thing for the human understanding as Rousseau at
a later period for the heart: a return to uncorrupted nature. This faith in
the unartificial, the original, the natural, this radical and naturalistic
tendency is characteristically French. The purification of the mind, its
deliverance from the rubbish of scholastic learning, from the pressure of
authority, and from inert acceptance of the thinking of others--this is
all. Descartes finds the clearest proof of the mind's capacity for truth in
mathematics, whose trustworthiness he never seriously questioned, but only
hypothetically, in order to exhibit the still higher certainty of the "I
think, therefore I am." He wants to give philosophy the stable character
which had so impressed him in mathematics when he was a boy, and recommends
her, therefore, not merely the evidence of mathematics as a general
example, but the mathematical method for definite imitation. Metaphysics,
like mathematics, must derive its conclusions by deduction from
self-evident principles. Thus the geometrical method begins its rule in
philosophy, a rule not always attended with beneficial results.
With this criterion of truth Descartes advances to the consideration of
ideas. He distinguishes volition and judgment from ideas in the narrow
sense (_imagines_), and divides the latter, according to their origin, into
three classes: _ideae innatae, adventitiae, a me ipso factae_, considering
the second class, the "adventitious" ideas, the most numerous, but the
first, the "innate" ideas, the most important. No idea is higher or clearer
than the idea of God or the most perfect being. Whence comes this idea?
That every idea must have a cause, follows from the "clear and distinct"
principle that nothing produces nothing. It follows from this same
principle, _ex nihilo nihil fit_, however, that the cause must contain as
much reality or perfection--_realitas_ and _perfectio_ are synonymous--as
the effect, for otherwise the overplus would have come from nothing. So
much ("objective," representative) reality contained in an idea, so much or
more ("formal," actual) reality must be contained in its cause. The idea
of God as infinite, independent, omnipotent, omniscient, and creative
substance, has not come to me through the senses, nor have I formed it
myself. The power to conceive a being more perfect than myself, can have
only come from someone who is more perfect in reality than I. Since I know
that the infinite contains more reality than the finite, I may conclude
that the idea of the infinite has not been derived from the idea of the
finite by abstraction and negation; it precedes the latter, and I become
conscious of my defects and my finitude only by comparison with the
absolute perfection of God. This idea, then, must have been implanted in me
by God himself. The idea of God is an original endowment; it is as innate
as the idea of myself. However incomplete it may be, it is still
sufficient to give a knowledge of God's existence, although not a perfect
comprehension of his being, just as a man may skirt a mountain without
encircling it.
Descartes brings in the idea of God in order to escape solipsism. So long
as the self-consciousness of the ego remained the only certainty, there was
no conclusive basis for the assumption that anything exists beyond self,
that the ideas which apparently come from without are really occasioned by
external things and do not spring from the mind itself. For our natural
instinct to refer them to objects without us might well be deceptive. It is
only through the idea of God, and by help of the principle that the cause
must contain at least as much reality as the effect, that I am taken beyond
myself and assured that I am not the only thing in the world. For as this
idea contains more of representative, than I of actual reality, I cannot
have been its cause.
To this empirical argument, which derives God's existence from our idea
of God (from the fact that we have an idea of him), Descartes joins the
(modified) ontological argument of Anselm, which deduces the existence of
God from the concept of God. While the ideas of all other things include
only the possibility of existence, necessary existence is inseparable from
the concept of the most perfect being. God cannot be thought apart from
existence; he has the ground of his existence in himself; he is _a se_
or _causa sui_. Finally, Descartes adds a third argument. The idea of
perfections which I do not possess can only have been imparted to me by a
more perfect being than I, which has bestowed on me all that I am and
all that I am capable of becoming. If I had created myself, I would have
bestowed upon myself these absent perfections also. And the existence of a
plurality of causes is negatived by the supreme perfection which I conceive
in the idea of God, the indivisible unity of his attributes. Among the
attributes of God his veracity is of special importance. It is impossible
that he should will to deceive us; that he should be the cause of our
errors. God would be a deceiver, if he had endowed us with a reason to
which error should appear true, even when it uses all its foresight in
avoiding it and assents only to that which it clearly and distinctly
perceives. Error is man's own fault; he falls into it only when he misuses
the divine gift of knowledge, which includes its own standard. Thus
Descartes finds new confirmation for his test of truth in the _veracitas
dei_. Erdmann has given a better defense of Descartes than the philosopher
himself against the charge that this is arguing in a circle, inasmuch as
the existence of God is proved by the criterion of truth, and then the
latter by the former: The criterion of certitude is the _ratio cognoscendi_
of God's existence; God is the _ratio essendi_ of the criterion of
certitude. In the order of existence God is first, he creates the reason
together with its criterion; in the order of knowledge the criterion
precedes, and God's existence follows from it. Descartes himself endeavors
to avoid the circle by making _intuitive_ knowledge self-evident, and by
not bringing in the appeal to God's veracity in _demonstrative_ knowledge
until, in reflective thought, we no longer have each separate link in the
chain of proof present to our minds with full intuitive certainty, but only
remember that we have previously understood the matter with clearness and
distinctness.
Our ideas represent in part things, in part qualities. Substance is defined
by the concept of independence as _res quae ita existit, ut nulla alia re
indigeat ad existendum_; a pregnant definition with which the concept of
substance gains the leadership in metaphysics, which it held till the time
of Hume and Kant, sharing it then with the conception of cause or, rather,
relinquishing it to the latter. The Spinozistic conclusion that, according
to the strict meaning of this definition, there is but one substance, God,
who, as _causa sui_, has absolutely no need of any other thing in order to
his existence, was announced by Descartes himself. If created substances
are under discussion, the term does not apply to them in the same sense
(not _univoce_) as when we speak of the infinite substance; created beings
require a different explanation, they are things which need for their
existence only the co-operation of God, and have no need of one another.
Substance is cognized through its qualities, among which one is pre-eminent
from the fact that it expresses the essence or nature of the thing, and
that it is conceived through itself, without the aid of the others, while
they presuppose it and cannot be thought without it. The former fundamental
properties are termed attributes, and these secondary ones, modes or
accidents. Position, figure, motion, are contingent properties of
body; they presuppose that it is extended or spatial; they are _modi
extensionis_, as feeling, volition, desire, representation, and judgment
are possible only in a conscious being, and hence are merely modifications
of thought. Extension is the essential or constitutive attribute of body,
and thought of mind. Body is never without extension, and mind never
without thought--_mens semper cogitat_. Guided by the self-evident
principle that the non-existent has no properties, we argue from a
perceived quality to a substance as its possessor or support. Substances
are distinct from one another when we can clearly and distinctly cognize
one without the other. Now, we can adequately conceive mind without a
corporeal attribute and body without a spiritual one; the former has
nothing of extension in it, the latter nothing of thought: hence thinking
substance and extended substance are entirely distinct and have nothing
in common. Matter and mind are distinct _realiter_, matter and extension
_idealiter_ merely. Thus we attain three clear and distinct ideas, three
eternal verities: _substantia infinita sive deus, substantia finita
cogitans sive mens, substantia extensa sive corpus_.
By this abrupt contraposition of body and mind as reciprocally independent
substances, Descartes founded that dualism, as whose typical representative
he is still honored or opposed. This dualism between the material and
spiritual worlds belongs to those standpoints which are valid without being
ultimate truth; on the pyramid of metaphysical knowledge it takes a high,
but not the highest, place. We may not rest in it, yet it retains a
permanent value in opposition to subordinate theories. It is in the
right against a materialism which still lacks insight into the essential
distinction between mind and matter, thought and extension, consciousness
and motion; it loses its validity when, with a full consideration and
conservation of the distinction between these two spheres, we succeed in
bridging over the gulf between them, whether this is accomplished through
a philosophy of identity, like that of Spinoza and Schelling, or by an
idealism, like that of Leibnitz or Fichte. In any case philosophy retains
as an inalienable possession the negative conclusion, that, in view of the
heterogeneity of consciousness and motion, the inner life is not reducible
to material phenomena. This clear and simple distinction, which sets bounds
to every confusion of spiritual and material existence, was an act of
emancipation; it worked on the sultry intellectual atmosphere of the time
with the purifying and illuminating power of a lightning flash. We shall
find the later development of philosophy starting from the Cartesian
dualism.
Descartes himself looked upon the fundamental principles which have now
been discussed as merely the foundation for his life work, as the entrance
portal to his cosmology. Posterity has judged otherwise; it finds his chief
work in that which he considered a mere preparation for it. The start from
doubt, the self-certitude of the thinking ego, the rational criterion of
certitude, the question of the origin of ideas, the concept of substance,
the essential distinction between conscious activity and corporeal being,
and, also, the principle of thoroughgoing mechanism in the material world
(from his philosophy of nature)--these are the thoughts which assure his
immortality. The vestibule has brought the builder more fame, and has
proved more enduring, than the temple: of the latter only the ruins remain;
the former has remained undestroyed through the centuries.
%2. Nature.%
What guarantee have we for the existence of material objects affecting our
senses? That the ideas of sense do not come from ourselves, is shown by
the fact that it is not in our power to determine the objects which we
perceive, or the character of our perception of them. The supposition that
God has caused our perceptions directly, or by means of something which has
no resemblance whatever to an external object extended in three dimensions
and movable, is excluded by the fact that God is not a deceiver. In
reliance on God's veracity we may accept as true whatever the reason
declares concerning body, though not all the reports of the senses,
which so often deceive us. At the instance of the senses we clearly and
distinctly perceive matter distinct from our mind and from God, extended
in three dimensions, length, breadth, and depth, with variously formed and
variously moving parts, which occasion in us sensations of many kinds. The
belief that perception makes known things as they really are is a prejudice
of sense to be discarded; on the contrary, it merely informs us concerning
the utility or harmfulness of objects, concerning their relation to man as
a being composed of soul and body. (The body is that material thing which
is very intimately joined with the mind, and occasions in the latter
certain feelings, _e.g._, pain, which as merely cogitative it would not
have.) Sense qualities, as color, sound, odor, cannot constitute the
essence of matter, for their variation or loss changes nothing in it; I can
abstract from them without the material thing disappearing.[1] There is one
property, however, extensive magnitude (_quantitas_), whose removal would
imply the destruction of matter itself. Thus I perceive by pure thought
that the essence of matter consists in extension, in that which constitutes
the object of geometry, in that magnitude which is divisible, figurable,
and movable. This thesis (_corpus = extensio sive spatium_) is next
defended by Descartes against several objections. In reply to the objection
drawn from the condensation and rarefaction of bodies, he urges that the
apparent increase or decrease in extension is, in fact, a mere change of
figure; that the rarefaction of a body depends on the increase in size of
the intervals between its parts, and the entrance into them of foreign
bodies, just as a sponge swells up when its pores become filled with water
and, therefore, enlarged. The demand that the pores, and the bodies which
force their way into them, should always be perceptible to the senses, is
groundless. He meets the second point, that we call extension by itself
_space_, and not body, by maintaining that the distinction between
extension and corporeal substance is a distinction in thought, and not in
reality; that attribute and substance, mathematical and physical bodies,
are not distinct in fact but only in our thought of them. We apply the
term space to extension in general, as an abstraction, and body to a given
individual, determinate, limited extension. In reality, wherever extension
is, there substance is also,--the non-existent has no extension,--and
wherever space is, there matter is also. Empty space does not exist.
When we say a vessel is empty, we mean that the bodies which fill it are
imperceptible; if it were absolutely empty its sides would touch. Descartes
argues against the atomic theory and against the finitude of the world, as
he argues against empty space: matter, as well as space, has no smallest,
indivisible parts, and the extension of the world has no end. In the
identification of space and matter the former receives fullness from
the latter, and the latter unlimitedness from the former, both internal
unlimitedness (endless divisibility) and external (boundlessness). Hence
there are not several matters but only one (homogeneous) matter, and only
one (illimitable) world.
[Footnote 1: They are merely subjective states in the perceiver, and
entirely unlike the motions which give rise to them, although there is
a certain agreement, as the differences and variations in sensation are
paralleled by those in the object.]
Matter is divisible, figurable, movable quantity. Natural science needs no
other principles than these indisputably true conceptions, by which all
natural phenomena may be explained, and must employ no others. The most
important is motion, on which all the diversity of forms depends. Corporeal
being has been shown to be extension; corporeal becoming is motion. Motion
is defined as "the transporting of one part of matter, or of one body, from
the vicinity of those bodies that are in immediate contact with it,
or which we regard as at rest, to the vicinity of other bodies." This
separation of bodies is reciprocal, hence it is a matter of choice which
shall be considered at rest. Besides its own proper motion in reference to
the bodies in its immediate vicinity, a body can participate in very many
other motions: the traveler walking back and forth on the deck of a ship,
for instance, in the motion of the vessel, of the waves, and of the earth.
The common view of motion as an activity is erroneous; since it requires
force not only to set in motion bodies which are at rest, but also to stop
those which are in motion, it is clear that motion implies no more activity
than rest. Both are simply different states of matter. Since there is no
empty space, each motion spreads to a whole circle of bodies: A forces B
out of its place, B drives out C, and so on, until Z takes up the position
which A has left.
The ultimate cause of motion is God. He has created bodies with an
original measure of motion and rest, and, in accordance with his immutable
character, he preserves this quantity of motion unchanged: it remains
constant in the world as a whole, though it varies in individual bodies.
For with the power to create or destroy motion bodies lack, further, the
power to alter their quantity of motion. By the side of God, the primary
cause of motion, the laws of motion appear as secondary causes. The first
of these is the one become familiar under the name, law of inertia:
Everything continues of itself in the state (of motion or rest) in which it
is, and changes its state only as a result of some extraneous cause. The
second of these laws, which are so valuable in mechanics, runs: Every
portion of matter tends to continue a motion which has been begun in the
same direction, hence in a straight line, and changes its direction only
under the influence of another body, as in the case of the circle above
described. Descartes bases these laws on the unchangeableness of God and
the simplicity of his world-conserving (_i.e._, constantly creative)
activity. The third law relates to the communication of motion; but
Descartes does not recognize the equality of action and reaction as
universally as the fact demands. If a body in motion meets another body,
and its power (to continue its motion in a straight line) is less than the
resistance of the other on which it has impinged, it retains its motion,
but in a different direction: it rebounds in the opposite direction. If, on
the contrary, its force is greater, it carries the other body along with
it, and loses so much of its own motion as it imparts to the latter. The
seven further rules added to these contain much that is erroneous. As
_actio in distans_ is rejected, all the phenomena of motion are traced back
to pressure and impulse. The distinction between fluid and solid bodies is
based on the greater or less mobility of their parts.
The leading principle in the special part of the Cartesian physics,--we
can only briefly sketch it,--which embraces, first, celestial, and, then,
terrestial phenomena, is the axiom that we cannot estimate God's power and
goodness too highly, nor ourselves too meanly. It is presumptuous to seek
to comprehend the purposes of God in creation, to consider ourselves
participants in his plans, to imagine that things exist simply for our
sake--there are many things which no man sees and which are of advantage
to none. Nothing is to be interpreted teleologically, but all must be
interpreted from clearly known attributes, hence purely mechanically.
After treating of the distances of the various heavenly bodies, of the
independent light of the sun and the fixed stars and the reflected light of
the planets, among which the earth belongs, Descartes discusses the motion
of the heavenly bodies. In reference to the motion of the earth he seeks a
middle course between the theories of Copernicus and Tycho Brahé. He agrees
with Copernicus in the main point, but, in reliance on his definition
of motion, maintains that the earth is at rest, viz., in respect to its
immediate surroundings. It is clear that the harmony of his views with
those of the Church (though it was only a verbal agreement) was not
unwelcome to him. According to his hypothesis,--as he suggests, perhaps an
erroneous hypothesis,--the fluid matter which fills the heavenly spaces,
and which may be compared to a vortex or whirlpool, circles about the sun
and carries the planets along with it. Thus the planets move in relation to
the sun, but are at rest in relation to the adjacent portions of the matter
of the heavens. In view of the biblical doctrine, according to which the
world and all that therein is was created at a stroke, he apologetically
describes his attempt to explain the origin of the world from chaos under
the laws of motion as a scientific fiction, intended merely to make the
process more comprehensible. It is more easily conceivable, if we think
of the things in the world as though they had been gradually formed from
elements, as the plant develops from the seed. We now pass to the Cartesian
anthropology, with its three chief objects: the body, the soul, and the
union of the two.
3. %Man.%
The human body, like all organic bodies, is a machine. Artificial automata
and natural bodies are distinguished only in degree. Machines fashioned by
the hand of man perform their functions by means of visible and tangible
instruments, while natural bodies employ organs which, for the most part,
are too minute to be perceived. As the clock-maker constructs a clock from
wheels and weights so that it is able to go of itself, so God has made
man's body out of dust, only, being a far superior artist, he produces a
work of art which is better constructed and capable of far more wonderful
movements. The cause of death is the destruction of some important part of
the machine, which prevents it from running longer; a corpse is a broken
clock, and the departure of the soul comes only as a result of death. The
common opinion that the soul generates life in the body is erroneous. It
is rather true that life must be present before the soul enters into union
with the body, as it is also true that life must have ended before it
dissolves the bond.
The sole principles of physiology are motion and heat. The heat (vital
warmth, a fire without light), which God has put in the heart as the
central organ of life, has for its function the promotion of the
circulation of the blood, in the description of which Descartes mentions
with praise the discoveries of Harvey _(De Motu Cordis et Sanguinis in
Animalibus_, 1628). From the blood are separated its finest, most fiery,
and most mobile parts, called by Descartes "animal spirits" _(spiritus
animales sive corporales_), and described as a "very subtle wind" or "pure
and vivid flame," which ascend into the cavities of the brain, reach
the pineal gland suspended in its center _(conarion, glans pinealis,
glandula_), pass into the nerves, and, by their action on the muscles
connected with the nerves, effect the motions of the limbs. These views
refer to the body alone, and so are as true of animals as of men. If
automata existed similar to animals in all respects, both external and
internal, it would be absolutely impossible to distinguish them from real
animals. If, however, they were made to resemble human bodies, two signs
would indicate their unreality--we would find no communication of ideas by
means of language, and also an absence of those bodily movements which
take their origin in the reason (and not merely in the constitution of the
body). The only thing which raises man above the brute is his rational
soul, which we are on no account to consider a product of matter, but which
is an express creation of God, superadded. The union of the soul or the
mind _(anima sive mens_) with the body is, it is true, not so loose that
the mind merely dwells in the body, like a pilot in a ship, nor, on the
other hand, in view of the essential contrariety of the two substances, is
it so intimate as to be more than a _unio compositionis_. Although the soul
is united to the whole body, an especially active intercourse between them
is developed at a single point, the pineal gland, which is distinguished by
its central, protected position, above all, by the fact that it is the only
cerebral organ that is not double. This gland, together with the animal
spirits passing to and from it, mediates between mind and body; and as the
point of union for the twofold impressions from the (right and left) eyes
and ears, without which objects would be perceived double instead of
single, is the seat of the soul. Here the soul exercises a direct influence
on the body and is directly affected by it; here it dwells, and at will
produces a slight, peculiar movement of the gland, through this a change
in the course of the animal spirits (for it is not capable of generating
motion, but only of changing its direction), and, finally, movements of the
members; just as, on the other hand, it remarks the slightest change in the
course of the _spiritus_ through a corresponding movement of the gland,
whose motions vary according to the sensuous properties of the object to be
perceived, and responds by sensations. Although Descartes thus limits the
direct interaction of soul and body to a small part of the organism, he
makes an exception in the case of _memoria_, which appears to him to be
more of a physical than a psychical function, and which he conjectures to
be diffused through the whole brain.
In spite of the comprehensive meaning which Descartes gives to the notion
_cogitatio_, it is yet too narrow to leave room for an _anima vegetativa_
and an _anima sensitiva_. Whoever makes mind and soul equivalent, holds
that their essence consists in conscious activity alone, and interprets
sensation as a mode of thought, cannot escape the paradox of denying to
animals the possession of a soul. Descartes does not shrink from such
a conclusion. Animals are mere machines; they are bodies animated, but
soulless; they lack conscious perception and appetition, though not the
appearance of them. When a clock strikes seven it knows nothing of the
fact; it does not regret that it is so late nor long soon to be able to
strike eight; it wills nothing, feels nothing, perceives nothing. The lot
of the brute is the same. It sees and hears nothing, it does not hunger or
thirst, it does not rejoice or fear, if by these anything more than mere
corporeal phenomena is to be meant; of all these it possesses merely the
unconscious material basis; it moves and motion goes on in it--that is all.
The psychology of Descartes, which has had important results,[1] divides
_cogitationes_ into two classes: _actiones_ and _passiones_. Action denotes
everything which takes its origin in, and is in the power of, the soul;
passion, everything which the soul receives from without, in which it can
make no change, which is impressed upon it. The further development of this
distinction is marred by the crossing of the most diverse lines of thought,
resulting in obscurities and contradictions. Descartes's simple, naïve
habits of thought and speech, which were those of a man of the world rather
than of a scholar, were quite incompatible with the adoption and consistent
use of a finely discriminated terminology; he is very free with _sive_, and
not very careful with the expressions _actio, passio, perceptio, affectio,
volitio_. First he equates activity and willing, for the will springs
exclusively from the soul--it is only in willing that the latter is
entirely independent; while, on the other hand, passivity is made
equivalent to representation and cognition, for the soul does not create
its ideas, but receives them,--sensuous impressions coming to her quite
evidently from the body. These equations, "_actio_--the practical, _passio_
= the theoretical function," are soon limited and modified, however. The
natural appetites and affections are forms of volition, it is true, but not
free products of the mind, for they take their origin in its connection
with the body. Further, not all perceptions have a sensuous origin; when
the soul makes free use of its ideas in imagination, especially when in
pure thought it dwells on itself, when without the interference of the
imagination it gazes on its rational nature, it is by no means passive
merely. Every act of the will, again, is accompanied by the consciousness
of volition. The _volitio_ is an activity, the _cogitatio volitionis_ a
passivity; the soul affects itself, is passively affected through its own
activity, is at the same instant both active and passive.
[Footnote 1: For details cf. the able monograph of Dr. Anton Koch, 1881.]
Thus not every volition, _e.g._ sensuous desire, is action nor all
perception, _e.g._ that of the pure intellect, passion. Finally, certain
psychical phenomena fall indifferently under the head of perception or of
volition, _e.g._, pain, which is both an indistinct idea of something and
an impulse to shun it. In accordance with these emendations, and omitting
certain disturbing points of secondary importance, the matter may be thus
represented:
COGITATIO.
¦
¦
ACTIO ¦ PASSIO
¦
¦
¦
(Mens sola; clarae et distinctae ¦ (Mens unita cum corpore;
ideae.) ¦ confusae ideae.)
¦
VOLITIO: ¦
6. Voluntas. 3b. Commotiones ¦ 3a. Affectus. 2. Appetitus naturales.
¦ intellectuales¦ ¦ ¦
¦ ¦ \ /
¦ ¦ --------v-------
Judicium. ¦ Sensus interni
---------------------------------+-----------------------------------
¦
¦
PERCEPTIO: 4. Imaginatio
------^------
/ \
5. Intellectus 4b. Phantasia. ¦ 4a. Memoria. 1. Sensus externi.
Accordingly six grades of mental function are to be distinguished: (1)
The external senses. (2) The natural appetites. (3) The passions (which,
together with the natural appetites, constitute the internal senses,
and from which the mental emotions produced by the intellect are quite
distinct). (4) The imagination with its two divisions, passive memory and
active phantasy. (5) The intellect or reason. (6) The will. These various
stages or faculties are, however, not distinct parts of the soul, as in the
old psychology, in opposition to which Descartes emphatically defends the
_unity of the soul_. It is one and the same psychical power that exercises
the higher and the lower, the rational and the sensuous, the practical and
the theoretical activities.
Of the mental functions, whether representative images, perceptions, or
volitions, a part are referred to body (to parts of our own body, often
also to external objects), and produced by the body (by the animal spirits
and, generally, by the nerves as well), while the rest find both object and
cause in the soul. Intermediate between the two classes stand those acts
of the will which are caused by the soul, but which relate to the body,
_e.g._, when I resolve to walk or leap; and, what is more important, the
_passions_, which relate to the soul itself, but which are called forth,
sustained, and intensified by certain motions of the animal spirits. Since
only those beings which consist of a body as well as a soul are capable of
the passions, these are specifically human phenomena. These affections,
though very numerous, may be reduced to a few simple or primary ones,
of which the rest are mere specializations or combinations. Descartes
enumerates six primitive passions (which number Spinoza afterward reduced
one-half)--_admiratio, amor et odium, cupiditas (désir), gaudium et
tristitia_. The first and the fourth have no opposites, the former being
neither positive nor negative, and the latter both at once. Wonder, which
includes under it esteem and contempt, signifies interest in an object
which neither attracts us by its utility nor repels us by its hurtfulness,
and yet does not leave us indifferent. It is aroused by the powerful or
surprising impression made by the extraordinary, the rare, the unexpected.
Love seeks to appropriate that which is profitable; hate, to ward off that
which is harmful, to destroy that which is hostile. Desire or longing looks
with hope or fear to the future. When that which is feared or hoped for
has come to pass, joy and grief come in, which relate to existing good and
evil, as desire relates to those to come.
The Cartesian theory of the passions forms the bridge over which its author
passes from psychology to ethics. No soul is so weak as to be incapable of
completely mastering its passions, and of so directing them that from them
all there will result that joyous temper advantageous to the reason. The
freedom of the will is unlimited. Although a direct influence on the
passions is denied it,--it can neither annul them merely at its bidding,
nor at once reduce them to silence, at least, not the more violent
ones,--it still has an indirect power over them in two ways. During the
continuance of the affection (e.g., fear) it is able to arrest the bodily
movements to which the affection tends (flight), though not the emotion
itself, and, in the intervals of quiet, it can take measures to render a
new attack of the passion less dangerous. Instead of enlisting one passion
against another, a plan which would mean only an appearance of freedom,
but in fact a continuance in bondage, the soul should fight with its own
weapons, with fixed maxims _(judicia)_, based on certain knowledge of good
and evil. The will conquers the emotions by means of principles, by clear
and distinct knowledge, which sees through and corrects the false values
ascribed to things by the excitement of the passions. Besides this negative
requirement, "subjection of the passions," Descartes' contributions to
ethics--in the letters to Princess Elizabeth on human happiness, and to
Queen Christina on love and the highest good--were inconsiderable. Wisdom
is the carrying out of that which has been seen to be best, virtue is
steadfastness, sin inconstancy therein. The goal of human endeavor is peace
of conscience, which is attained only through the determination to be
virtuous, i.e., to live in harmony with self.
Besides its ethical mission, the will has allotted to it the theoretical
function of affirmation and negation, i.e., of judgment. If God in his
veracity and goodness has bestowed on man the power to know truth, how is
misuse of this power, how is error possible? Single sensations and ideas
cannot be false, but only judgments--the reference of ideas to objects.
Judgment or assent is a matter of the will; so that when it makes erroneous
affirmations or negations, when it prefers the false judgment to the true,
it alone is guilty. Our understanding is limited, our will unlimited; the
latter reaches further than the former, and can assent to a judgment
even before its constituent parts have attained the requisite degree of
clearness. False judgment is prejudgment, for which we can hold neither God
nor our own nature responsible. The possibility of error, as well as the
possibility of avoiding error, resides in the will. This has the power to
postpone its assent or dissent, to hold back its decision until the ideas
have become entirely clear and distinct. The supreme perfection is the
_libertas non errandi_. Thus knowledge itself becomes a moral function; the
true and the good are in the last analysis identical. The contradiction
with which Descartes has been charged, that he makes volition and cognition
reciprocally determinative, that he bases moral goodness on the clearness
of ideas and _vice versa_, does not exist. We must distinguish between a
theoretical and a practical stadium in the will; it is true of the latter
that it depends on knowledge of the right, of the former that the knowledge
of the right is dependent on it. In order to the possibility of moral
_action_ the will must conform to clear judgment; in order to the
production of the latter the will must _be_ moral. It is the unit-soul,
which first, by freely avoiding overhasty judgment, cognizes the truth, to
exemplify it later in moral conduct.