Rene Descartes 1596

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Descartes Meditation 1 2
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Rene Descartes1596 - 1650

• A rationalist looking for certainty. Challenging
  the empiricism of Aristotle
• Produced several sceptical arguments which have
  proven very hard to counter to this day.
• Founder of modern philosophy Placed the
  question, What can I know? and a systematic
  way of trying to arrive at the truth at the
  centre of Philosophy.

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Rene Descartes (1596 1650)

• Descartes came from La Haye in France.
• Educated at La Fleche Came to the opinion that
  with the exception of maths, most of the
  subjects taught were too uncertain to count as
  knowledge.

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Descartes

• France in 1600s an age of doubt.

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Descartes

• Galileo came into conflict with church for
  championing the Copernican view that the earth
  was not the centre of the universe.

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Descartes

• Galileo argued that the Earth rotated around the
  Sun and rejected the Biblical view that placed
  the Earth at the centre of the Universe.

V.
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Descartes

• Galileo also argued against the physics of
  Aristotle. Galileo used rational argument to do
  this.

The Rationalism of Galileo What do you think fall
faster - light objects or heavy objects?
Aristotle believed that heavy objects fell more
rapidly than light objects. Galileo purely by
reason and logic argued that this couldnt be the
case. He argued that if you tied a light object
to a heavy object, the two objects would in
effect become one and if Aristotle was right
fall more rapidly than the two individual
objects. However it could also be argued that the
lighter object would drag back the heavier object
and therefore the objects would not fall so
rapidly !!!! So Galileo concluded that Aristotle
theory led to ridiculous conclusions and couldnt
be true. Philosophers recognise two main ways of
obtaining knowledge by means of the senses and
by means of reason., empiricism and rationalism.
This is a classic example of rationalism
working something out purely by reason. Descartes
was very impressed by this way of thinking
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Descartes

• The 1600s was a time of great conflict in the
  church as the Protestants broke away from the
  Catholic church in the movement known as the
  Reformation.
• This undermined the authority of the Church and
  created confusion and doubt.

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Descartes

• The discovery of the Americas revealed an alien
  culture with a completely different world-view.
• This engendered feelings of cultural relativity.

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Descartes

• All this led to a deep scepticism on the one hand
  and, on the other, a willingness to accept just
  about any old nonsense.

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Descartes

• Descartes looking for away out of all this doubt.
• Liked the certainty of mathematics.
• Method of radical doubt Question and challenge
  everything to see what remained. Treat as false
  anything which is dubitable.
• Looking for a firm foundation for knowledge.

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Descartes

• In 1641 Descartes published the Meditations.

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Meditation 1

• In the Meditations Descartes looks for certain
  knowledge by doing away with any knowledge which
  might be uncertain in any way.
• So before he can build up knowledge he needs to
  demolish everything that is doubtful.
• Elsewhere he likens the process to tipping out a
  basket full of apples to identify the rotten ones.

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Descartes Mediation 1,17-18

• Descartes is therefore not a sceptic.
• He uses sceptical arguments to identify those
  beliefs which escape criticism This method is
  known as Cartesian doubt.
• He tells us that he is not going to individually
  examine every belief he holds but examine groups
  of ideas that share something in common (eg
  gained through the senses)
• Not only beliefs that are obviously wrong but
  beliefs that are in any way doubtful are to be
  set aside.
• He likens the process to demolishing a building
  by destroying its foundations (rather than taking
  it apart a brick at a time from the top down.)

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Meditation 1, 18-19(See P.75 Hatfield)

• Knowledge gained through the senses can be
  unreliable .
• Things in the distance look smaller than things
  close up.
• But senses at other times deliver reliable
  information.
• You couldnt possibly deny that your senses were
  giving youaccurate information about things
  close up, like that you have a body, unless you
  were insane.

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Meditation 1, 19

• But how do I know that I am not dreaming that I
  am sitting by the fire in my dressing gown?
• There are no definite signs which prove that we
  are awake.
• It could all be dream in which case all sense
  experience becomes unreliable.
• So aposteriori knowledge is challenged by the
  dream argument.

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Meditation 1, 19-20page 77

• But even if it is a dream some knowledge would
  still survive.
• Artists create fantastic creatures by fusing
  together parts from different real animals. So
  too our dreams are composed of elements that
  really exist such as eyes, heads and hands.
• But artists also produce images that have no
  basis in reality at all, but even then these
  images are made up of simple basic things, like
  colour and shape. so these things, at least, must
  exist even if this is a dream.

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Meditation 1, 20

• So even if this is a dream the following would
  still seem to be real
• That physical things exist. That physical
  things have shape, quantity (size and number).
  That space and time must exist.
• Physics, astronomy medicine all doubtful
  because based on secondary qualities but since
  arithmetic and geometry based on primary
  qualities they are based on something certain.
• So awake or dreaming mathematical truths would
  still be true.
• In other words apriori knowledge manages to
  survive the dream scenario

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Meditation 1, 21Page 80gt

• Now presents a challenge to mathematical
  knowledge.
• How do I know everything I take to be real is not
  being planted directly in my mind by a deceiving
  God?
• If this were the case then even apriori
  mathematical knowledge is cast into doubt.
• But God is no deceiver

?
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Meditation 1, 21Page 82gt
?

• The position of universal doubt is developed
• But God does allow me to be deceived from time to
  time. This happens - so being deceived is perhaps
  not inconsistent with even a good God
• Descartes then considers other alternative
  theories of human origin we could have been
  created by 1) chance or 2) an infinitely long
  chain of causes.
• But these origins are less powerful than being
  created by an all-powerful God and therefore if
  we came about in this way we are even more likely
  to be deceived all the time.
• The conclusion here is that, on either
  explanation, we could be being deceived all the
  time.
• He concludes that everything he once believed in
  is now cast into doubt and he adds -not for
  trivial reasons but for valid reasons.

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Meditation 1, 22Page 82gt

• But his old beliefs have become a matter of habit
  (because they are highly probable) so he adopts a
  mental strategy to keep them at bay. He is going
  to pretend that his former beliefs are wholly
  false (not just doubtable) and this will act as a
  counterbalance to his habitual pattern of
  thinking.
• As a dramatic device to achieve this he is going
  to imagine not God, but that an evil genius
  (demon) has taken over his mind.

• Note- the evil demon is not necessary for his
  argument. It is rather a psychological device he
  employs to keep him on track in his meditations.

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End of meditation 1.
By the end of Meditation 1 Descartes has
demolished certainty in any knowledge at all.
He has arrived at a position of total universal
doubt.
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Meditation 2. 24

• Begins meditation 2 by declaring his desire to
  find an Archimedean point, a certainty upon
  which he could develop knowledge.
• He suggests that perhaps the only thing certain
  is that nothing is certain.
• But then he realises that if he has managed to
  persuade himself that nothing is real, he must
  exist to be persuaded and if he is being deceived
  by a deceiver then he must exist to be deceived
  and so he finds a certainty I am, I exist is
  necessarily true.

Archimedes declared that if he had long enough a
lever and a fulcrum, upon which to rest it, he
could move the whole World.
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Meditation 2. 24

• I am, I exist is necessarily true. In a
  previous work, The Discourse, on Method this
  conclusion had been expressed as I think
  therefore I am. or in Latin Cogito ergo sum.
  This conclusion is therefore known as the cogito.

I am, I exist is necessarily true.
(Meditations) I think therefore I am
(Discourse on method) Je pense donc je suis
(French) Cogito ergo sum (Latin)
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Whats wrong with the cogito?1) Is there a
questionable suppressed premise?

• Most criticism of cogito in its earlier format
  I think therefore I am, in the Discourse on
  Method.

1) The suppressed premise First raised by
Lichtenberg I think Thinking things
exist Therefore I am
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Whats wrong with the cogito?1) Is there a
questionable suppressed premise?

• The suppressed premise
• I think
• Thinking things exist
• Therefore I exist
• This premise is questionable -Do the existence of
  thoughts necessarily imply a thinker? David Hume
  argued that we have no right to assume this, as
  does the anatta (no-self) doctrine of Buddhism.
  Perhaps Descartes should have said, There is
  thinking going on therefore there are thoughts.
  The cogito therefore doesnt actually establish
  the existence of a self.
• I is merely a linguistic convenience. It
  doesnt actually refer to anything, no more so
  than the It in It is raining.
• It can be argued that Descartes strays from his
  rationalistic agenda here since thinking things
  exist is an aposteriori, empirical observation.

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Whats wrong with the cogito?1) Is there a
questionable suppressed premise?

• The suppressed premise Counter arguments
• I think
• Thinking things exist
• Therefore I exist
• Ownerless, thinkerless thoughts pretty weird!
• The suppressed premise argument assumes that
  Descartes intended the cogito as a piece of
  syllogistic (deductive) logic. However Descartes
  did not intend the cogito to operate this way.
  The meditations should be seen as a course in
  guided self-discovery and the cogito as a
  self-authenticating proposition. According to
  Cottingham, Descartes expressly made this point
  to Leibniz at the time.
• Descartes restates the cogito in the Meditations
  as I exist is necessarily true. to clarify this
  and overcome the criticism

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Whats wrong with the cogito?2) The cogito is
circular.

• I think
• Therefore I am

• According to Bertrand Russell the cogito is
  circular since it assumes what it is setting out
  to prove.

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Whats wrong with the cogito?2) The cogito is
circular. Counter argument

• I think
• Therefore I am

• But as with the suppressed premise argument,
  Descartes never intended the cogito to be a
  deductive argument and his restatement of the
  cogito in the Meditations (I am, I exist is
  necessarily true) overcomes this criticism.

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Whats wrong with the cogito?2) The cogito is
trivial - It doesnt tell us anything of
significance.

• Most critics of Descartes are willing to grant
  him the cogito but would argue that if this is as
  far as his argument goes then he has established
  very little indeed. His task is to overcome
  scepticism and produce some certainty about the
  world out there.
• He claims this is his Archimedian point, his
  foundational proposition upon which he will build
  knowledge but as we see he abandons this as a
  foundation and uses arguments for God as his
  means of overcoming scepticism.

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Whats wrong with the cogito?3) Could you exist
without a body?
Descartes is a dualist - he believes in the
existence of a body and a mind. He argues that
although he may be deceived into believing he has
a body, by an evil demon, he must have a mind
since he has thoughts. This view-point is
contrary to modern neuro-science (study of the
brain) which takes a monist position we only
have a body. Thoughts exist in the brain nerve
cells. Without a brain there can be no thoughts.
If you cant exist without a body then Descartes
position is seriously undermined.
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Meditation 2, 25 - 33

• Descartes argues that he has more certainty of
  the existence of the mind than that of the body
  because whereas he may be deceived into believing
  that a physical world (including his body)
  exists, he, as a mind, must exist to be deceived
  in the first place.
• He says that although he cant establish that he
  has a body, he can establish that he is a
  thinking thing.

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Meditation 2, 25 33The wax argument (30)
To further demonstrate the limitations of the
senses, Descartes proceeds with what is known as
the Wax Argument. He considers a piece of wax
his senses inform him that it has certain
characteristics, such as shape, texture, size,
colour, smell, and so forth. When he brings the
wax towards a flame, these characteristics change
completely. However, it seems that it is still
the same thing it is still a piece of wax, even
though the data of the senses inform him that all
of its characteristics are different. Therefore,
in order to properly grasp the nature of the wax,
he cannot use the senses he must use his mind.
The wax example is used to show the superiority
of rationalism over empiricism. Since the wax
changes all the time it is reason rather than the
senses which allow us to know the wax.