René Descartes [1598-1650]
1.1
Descartes problem
[Like Bacon] Descartes sets his face against old authorities and emphasized the practical character of philosophy and [unlike Bacon] he took mathematics as the model of his philosophical method…he offers a program of human knowledge and sought to construct a system of thought which would possess the certainty of mathematics. He was in agreement with the great natural scientists of the new era: everything in [external] nature must be explained mechanically – without forms or essences, but he also accepted the fundamental principles of the time-honored idealistic philosophy and attempted to adapt them to the demands of the new science: his problem was to reconcile the mechanism of nature with the freedom of the human soul
1.2
Classification of the sciences
[1] The first part of true philosophy is metaphysics, which contains principles of knowledge – what came to be called epistemology, such as the definition and principle attributes of God, immortality of the soul, and of all the clear and simple ideas that we possess;
[2] physics, true principles of
material things, structure and origin of the universe, nature of the earth, of
plants, animals and man
1.3
Method and criterion of knowledge
Aim: to find a body of certain and self-evident truths. The
method of mathematics is a key: begin with axioms which are self-evident, then
deduce logical consequences…This method must be extended to philosophy.
Descartes combs through the elements and levels of knowledge, examines and
discards all those claims which are uncertain and arrives at…one thing is
certain: that I doubt or think – It is a contradiction to suppose [think] that
that which thinks does not exist at the very time when it thinks. [Perhaps
Descartes’ analysis proves only: thought occurs]
1.4
Proofs of the existence of God
Descartes provided a detailed proof according to the recipe:
I, a finite being, cannot conceive a greater being through my own lesser
intellect. I conceive the perfect being God – this concept can only have been
placed thereby God – who, therefore, exists. Descartes gives a detailed
construction of the proof and a refutation of certain counter-arguments. The
interest in such arguments – to me – is the idea of construction of metaphysics
[whether or not the specific construction is valid]
1.5
Truth and error
The source of [human] error is the disparity between the
finitude of human intellect and the infinitude of the human will
1.6
Existence of the external world
God induced in us a deeply rooted conviction of the existence
of an external world; if no such world existed he could not be defended against
the charge of being a deceiver [similar to the evolutionary argument]. The
existence in my mind of dreams and hallucinations is not a counter argument
since God has endowed me with the power of intellect to dispel and correct such
delusions. This God is not a deceiver, but a truthful being, and our sensations
must therefore by caused by real bodies…Descartes, strictly speaking, affirms
one absolute substance – God and two relative substances – mind and body, which
exist independently of each other but depend on God…Descartes holds that God
has given the world a certain amount of motion: motion is constant: the germ
of the principle of conservation of energy
1.7
Relation of mind and body
We cannot conceive of mind or soul without thought: the soul
is res cogitans: I have a clear and distinct idea of myself in so
far as I am only a thinking and un-extended thing. Hence it is certain that I
[my mind] through which I am what I am, is entirely and truly distinct from my
body and may exist without it…What attracted Descartes to this extreme dualism
was that it left nature free for the mechanical explanation of natural science
[and the mind to idealism, etc., or to the Church]…These two substances exclude
each other: mind cannot cause changes in the body and body cannot cause changes
in the mind…However there are facts which point to the intimate union of matter
and mind [appetites, emotions, sensations…]…God has put them together, but they
are so separate in their nature that either could be conserved by God apart
from the other. Descartes’ vacillation is due to his desire to explain the
corporeal world mechanically but retain a spiritual principle…yet at times he
accepts the theory of causal interaction without hesitation
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