RENE DESCARTES 1596--1650
His life: see video.
His works:
Regulae ad directionem
ingenii 1628, published posthumously;
Le Monde, 1633, published
posthumously;
Discors de la Methode,
1637;
Meditationes de prima philosophia,
1641, French edition 1647;
Principia Philosophiae,
1644, French edition 1647;
Les Passions de l'Ame 1649.
Descartes'
intentions and his Method.,
Descartes thinks he can make a new start in knowledge -because he has come
across a particular method, which he has already applied with some success.
This method = a generalization of the procedure of mathematicians, the
essentials summed up in his four Rules -- see Discourse 2.
In first or fundamental philosophy however the method is qualified by the
fact that we can only use analysis, not
synthesis, whereas in maths proper both methods can
be used reversibly.
To use synthesis we would have to presuppose the existence of God and
also that God had to create the world.
This differentiates Descartes from Spinoza.
Descartes intends not only to found knowledge, to provide a new basis, but
to build significantly on the foundations.
Compare his comparison of philosophy to a tree:
An Introduction to The Meditations:
·
The title: meditations rather than a treatise --because the order
is analytic.
·
The aim of the thinking, the problem to be solved: to found
knowledge, to provide a secure base for the rest. The method: analysis, working like a
mathematician. Find an indubitable
starting point, proceed from there by clear and
evident steps, until you have fully solved the problem. How to find the indubitable starting point:
universal, radical methodic doubt. Once
you have found this starting point, proceed from there by clear and evident
steps, jumping from one idea whose correspondence with reality has been shown
to another.
Plan of the six Meditations: -- two hemispheres of three each, the first dominated by universal doubt, the
second by the veracity of God, as follows:
Notes on each of the Meditations:
First Meditation: About the Things We May Doubt Universal, radical, methodic doubt, to
find an indubitable starting point, covering I)the existence of the world; 2)my
here and now physical existence in the world; 3)arithmetic and geometry.
Of two kinds: (a)hyperbolic doubt; (b)metaphysical
doubt (le malin genie).
Second Meditation: On the Nature of the Human Mind; and that it is Easier to Know than the
Body.
The indubitable starting point, and what is involved in It. Three stages:
1) 'I am': Cogito, ergo sum =
the indubitable starting point, the real existence of that which doubts;
2) what
am I? A thing which thinks: sum res cogitans;
3) what
is a thing which thinks?
A thing which doubts, affirms, denies, wills, does
not will. Also imagines.
Also seemingly feels or senses or perceives.
Also works as active possibility condition for all knowledge, even of the
sensory world (the piece of wax).
Third Meditation: Of God; that He exists.
Why God? Because of its strategic
significance -- knowledge of the existence of God who can neither deceive nor
be deceived will allow a radical resolution of metaphysical doubt and of
hyperbolic doubt precisely as hyperbolic in respect of everything else.
.the experience of the Cogito provides us with a criterion of truth --we
may accept whatever is a clear and evident as that.
What I need to get out of the subjective field of the here and now cogito:
I) a self-evident principle of causality: C = E (i.e. nothing gives what it
hasn't got);
2) an idea in my mind which I couldn't have caused
and which only God could have caused: my positive idea of the Infinite. Note that the proof of God at this stage is a
posteriori, from my experience of myself-thinking-a-certain-idea to God via a
principle of causality. This is in line
with the method of analysis, which is why he can't use the ontological argument
just yet --comes only in the Fifth Meditation, where its function is to tell us
about the mode of existence of God.
Fourth Meditation: Of Truth and Error.
If God is truthful, however, how can there be error, as there so obviously
is, and how may we avoid it?
Two considerations:
(i) Metaphysically, error is simply an absence of
knowing, a non-being. Sometimes however
it seems to be more like a 'privatio' than a simple
non-being, thus a second consideration.
(ii) Psychologically, has its origin in us, in the
distinction between will and intellect and the absolute freedom of the
will. Given this how to prevent error:
only affirm and deny what we think we know clearly and distinctly and with
evidence.
Fifth Meditation: Of the Essence of Material Things; and of God, once more
1) the essence of material things = extension
--only primary qualities are real, only what we can clearly and distinctly
conceive;
2) the 'ontological argument', in Descartes also
two arguments: (a)God = supremely perfect being; existence is a perfection;
therefore God exists. (b)God = supremely perfect being; eternal and necessary
existence is a perfection. God has
necessary and eternal existence.
Therefore also God exists.
Sixth Meditation: Of the Existence of Material Things, and of the Real Distinction between
the Soul and Body of Man .
·
Certain ideas I have which don't
appear to come from myself, leading to an irresistible determination to believe
in an external world. Therefore a
material world must exist, otherwise God is a deceiver;
·
For similar reasons, myself as in
union with a body; body another substance, distinct from the mind which I was
certain of existing while still denying the body; but very closely united
--cf. pain and
pleasure --not like a pilot in a ship.
This is not the end of the story, of course --just the basis, giving the
tree good, solid roots.
Comments on Descartes:
·
The doctrine of primary and secondary qualities -
already/also in Galileo, and found also in Locke, the first of the
'empiricists'. Destroyed in
philosophy by Berkeley and Hume: primary qualities by themselves cannot
give a conception of matter.
·
The positive concept of the Infinite --otherwise I
wouldn't know myself or other things as imperfect. A positive, not merely negative idea --not
however a comprehension.
·
The fatal doctrine: only to accept as real what we can intuit in
a clear and distinct idea.
Consequence: an effective reduction of reality to that which I/we can
clearly understand and be certain of. A
new kind of anthropomorphism.
·
Another legacy of Descartes: Dualism: two worlds,
Thought, Extension, Minds, Bodies. A
simplification/falsification of both Mind and Nature. And makes the unity of the human being almost
inconceivable. Descartes: they interact
via the pineal gland.