|
 Philosopher
of the Month
August
2001 - Rene Descartes
Jonathan
Walmsley
Descartes
set out to destroy Aristotelian philosophy. He was entranced by
the certainty that mathematics conferred upon its conclusions, and
Kepler and Galileo had shown that mathematics had application to
the natural world. Aristotle's philosophy placed no emphasis upon
irrefutable certainty and relied upon consensus as a basis for knowledge.
Nor did Aristotelian natural philosophy lend itself to mathematicisation.
It was Descartes's aim to underpin his knowledge of the world with
unshakable foundations by importing the certainty of mathematics
into the physical and metaphysical spheres.
This
was no simple task - where was the purity of mathematics in the
chaos of experience? To find the wanted certainty, Descartes had
to remove any hint of doubt from the premises upon which he would
build his new knowledge. It was his methodology at this point that
set him apart from his predecessors. He chose not to rely upon popular
opinion, or the writings of the ancients. He even questioned his
own perceptions, opinions and knowledge.
Rather
than review each of his opinions individually, Descartes examined
the foundation on which they were all based - perceptual experience.
If this foundation was found wanting, the structure built upon it
should be dismissed. Descartes recognised that his perceptual faculties
misled him through illusion and hallucination. In dreams he had
experiences which were not veridical. Perception produced only dubitable
beliefs.
But
the possibility of doubt was difficult to maintain against the vigour
of sensation. To counter this weakness, Descartes supposed there
was a powerful evil demon whose vocation it was to deceive us. Such
a mighty creature would be well equipped to feed you sensations
of all sorts. The world would seem to you as it does now, but there
would be nothing correspondent to any of your perceptions. The scepticism
engendered by this creature would cast doubt on all beliefs derived
from sensation. All that remained after this epistemic cleansing
would be certain.
But
what was left? Certainly not the objects around me or even my body.
Knowledge of these was based on sensation and sensation could not
guarantee certainty. What then could be known? Must I doubt the
existence of everything? Might I doubt that I exist? It is here
that the doubt comes to an end. I cannot doubt that I exist - for,
Descartes maintains, in this very act of doubting I am existing.
'I think', declared Descartes, 'therefore I am'. But what is the
'I' that exists? It is not some material thing - it is possible
to doubt that all material things exist, but not that 'I' do. 'I'
am a thinking thing and a thing, moreover, that certainly exists.
This was Descartes Archimedean point, from which he would move the
world.
Yet
in comparison to our former knowledge, this point seems hopelessly
small. Where previously we had the richness of the entire world
in which to believe, now we only have one small set of disembodied
thoughts and memories. How can we move from this minute point of
thought to the massive pageant of experience? Our knowledge of the
world had to be constructed of the most solid of certainties. Descartes
thought that such material could be found in God. If God truly existed,
the things that we clearly and distinctly perceive must surely exist,
as God is benevolent and would not allow us to be deceived. A demonstration
of the necessary existence of God is thus crucial to Descartes'
plan. It is consequently unfortunate that the arguments that Descartes
advanced to prove the existence of God were all flawed.
Descartes
did destroy Aristotle, but his own programme was a failure. Yet
it was not his success that is important, it was radical nature
of his strategy and the way in which he attempted to execute it.
His emphasis upon mathematical certainty and universal law had a
profound effect upon science. This soon found profitable expression
in Newton's hands. Descartes' individualism defined modernism in
philosophy. But the sceptical spectre of the evil demon still haunts
modern philosophical work - it is a possession that no one has yet
managed to exorcise, except by neglecting to consider it in the
first instance. Descartes was the making of science and the downfall
of philosophy.
Suggested
reading
Meditations, René Descartes (many editions)
Descartes, John Cottingham (Blackwell)
A
new philosopher of the month will be featured from mid-September
2001
Join
Our Café mailing list
To
receive *very* short messages, letting you know when the Café
has been updated, just fill in your email address below - and press
submit.
[If
you wish to unsubscribe from the mailing list, simply fill in your
subscriber email address, select "Unsubscribe", and press Submit.]
Previous
Philosophers of the Month
|
