Ren Descartes

1
René Descartes

• Introduction

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René Descartes (1596-1650)
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Who was Descartes?

• Son of a minor noble family
• Student with the Jesuits at La Flèche
  (1604-1612), studied logic, Aristotelian
  Scholastic philosophy, some maths
• Law degree 1616 (following his father)
• Soldier (a nobles occupation) (1618-19)
• Peripatetic in Europe 1620-1628
• Settled in Holland 1628 pursued his studies
  privately, corresponded with other philosophers
  (scientists) such as Mersenne
• Died in Stockholm, 1650.

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Major Themes

• Reconstruction of epistemology on new foundation
• Man is a thinking thingthis is certain animals
  are mere machines
• Mind-Body Dualism res cogitans vs res extensa
• Innate Ideas (cf. Locke!)
• Proof of Existence of God starting with human
  imperfection doubt
• Universe/nature as mechanism

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Descartes Major Works

• Discourse on the Method for Rightly Conducting
  Ones Reason and for Seeking Truth in the
  Sciences (1637)in French
• La Géométrie (algebra applied to geometry)
• La Dioptrique (optics)
• Les Météores (meteorology)
• Meditations on First Philosophy (1641)in Latin
  replies to readers responses to DM
• What is the significance of Descartes using
  these different languages?

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Discourse on Method (1637)

• Contains reflections from when Descartes was in
  military service in Germany (1619)
• Arises from the insights of his three dreams (see
  Gaukroger, 106-9)
• Travel opened his eyes to the role of prejudice
  in our thinking (cf. Bacons idols)
• DM a stylized intellectual autobiography
• Ds relativism leads to skepticism.

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Appendices to DM

• La Géométrie and La Dioptrique
• Les Météores attempts to put the study of weather
  on a scientific basis. However many claims are
  not only wrong, but could have easily been seen
  to be wrong if he had done some simple
  experiments. Descartes claims ... we see by
  experience that water which has been kept on a
  fire for some time freezes more quickly than
  otherwise, the reason being that those of its
  parts which can be most easily folded and bent
  are driven off during the heating, leaving only
  those which are rigid.

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DM, Pt. 1 Descartes Education

• I took especially great pleasure in mathematics
  because of the certainty and the evidence of its
  arguments.
• Of philosophy I shall say only thatthere is
  nothing about which there is not some disputeand
  thus nothing that is not doubtful.
• As to the other sciences, since they derive
  their principles from philosophy, I judged that
  one could not have built anything solid upon
  foundations having so little firmness.

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DM, Pt. 2 Prelude to Method

• (1) Metaphor of the well-engineered town, e.g.
  city-state of ancient Sparta (8th-4th cents.BCE)
  Descartes Lycurgus lawgiver of the Mind.
• (2) Reflects on reasoning by man of good sense
  (good sense or reasonis naturally equal in all
  men Pt. 1).
• (3) Expunges all prior beliefs, but does not
  consider himself an example for everyone since he
  had the opportunity to travel, see diversity of
  beliefs, cultures, and free himself from
  prejudices.
• (4) Rejects Aristotelian syllogism.

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The Rules of Method

• Accept only that which is evidently true avoid
  precipitous judgment and prejudice accept only
  clear and distinct ideas (intuitions, immediate
  apprehensions of truth).
•  Divide, dissect down to smallest possible units
  of analysis (see vivisection in pt. 5)
• Proceed from simplest (atoms or cells) to more
  complex in an orderly manner (e.g. biology,
  mechanics)
• Make enumerations so complete and reviews so
  general that nothing is omitted.

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Discourse, Pt. 3

• Adopts a provisional morality, a home in which to
  reside while the new house under construction.
• Accepts laws, religion and other external
  conditions in his culture (cf. Socrates)
• Wishes to know himself first (Socratic idea the
  unexamined life is not worth living).
• Descartes Stoicism conquer myself rather than
  fortune.
• Rejects Skepticism for its own sake wants to
  focus on attaining certainty.

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Pt. 4 Doubt, Dualism, and God

• 1. Hyperbolic doubt senses deceive, dreams
  appear real
• 2. Doubt presupposes thought
• 3. Thinking (cogito) presupposes existence and is
  the only certainty
• Needs no place and depends on no material
  thing his soul is entirely distinct from the
  body, and even if there were no body, the soul
  would not cease to be all that it is.
• The locus of knowledge of the empirical world
  is removed from the empirical world (Gaukroger,
  319).

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ExkursusThe Mind-Body Relation

• nerves are transducers
• sensations do not reveal properties of
  extramental reality (cf. Locke)
• pineal gland is seat of sensory modules (see next
  slide)
• sensations do not inform the mind about
  extramental things rather, they enable soul to
  assess utility of extramental objects.

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The Pineal Gland (at H)
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Descartes Proof of Gods existence

• 4. His doubt indicates his lack of perfection
  (more perfect to know than to doubt)
• 5. Seeks a being more perfect than himself,
  namely, God, who is not composed, but unitary
  (composition imperfection). This is a clear
  and distinct idea, immediately intuited once he
  has grasped point 4.
• 6. Innate idea of God placed in him by God, since
  the receiving of this idea from nothing is a
  manifest impossibility.
• 7. Descartes Platonism liftminds above
• sensible things.

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Descartes, DM, Pt. 5

• Doctrine of innate idea of natural laws (Le
  Monde Hackett, p. 23).
• Imagines an alternate, identical world according
  to exactly the same physical laws I here
  resolved to leave all this world to their
  disputes and to speak only of what would happen
  in a new world were God now to create enough
  matter to make it up, somewhere in imaginary
  space (Hackett, p. 24).

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DM, Pt. 5

• Anatomical and physiological studies (pp. 26-34)
• On his mechanical model of nature, Descartes
  posits the doctrine of the Animal-Machine an
  animal accordingly does not feel pain when it is
  vivisected (so why does it make sounds?)
• There are 3 kinds of soul in the world, BUT only
  the human soul is rational (has logos) animals
  have non-rational, animal souls.
• How does Descartes demonstrate the difference
  between human and animal, and why is he so
  concerned with this difference?

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Pt. 6 Descartes practical programme

• Descartes empirical concerns
• -conquest of nature we should make ourselves
  masters and possessors of nature
• -medicineone of the chief areas to be
  investigated
• -experiments to further medical and other
  scientific work, but too many for Descartes to
  perform on his own
• -hence, the need to organize science, engage in
  cooperative experimental endeavour and
  communicate experimental results.

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Pt. 6 Descartes practical programme

• I see quite well in what direction one must go
  in order to do the majority of the experiments
  that can serve this purpose to search for some
  experiments that are such that their outcomes are
  not the same but I also see that they are of
  such a nature and in such a multitude that
  neither my hands nor my financial resources
  would be sufficient for all of themI urge all
  those who desire the general well being of mento
  communicate those experiments that they have
  already done as well as to help me in the search
  for those that remain to be done.