Rene Descartes and the possibility of knowledge

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Rene Descartesand the possibility of knowledge
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Method of Doubt

• Not a real doubt but a concern for how he can
  know what he knows
• thus a thought experiment
• 1. Examination of all received beliefs, and
  refusal of authority.
• 2. Recognition that senses sometimes deceive us.
  Thus, though some sensory evidence could only be
  rejected by a lunatic, our beliefs about the
  world might be false (dreams, hallucinations,
  etc.).
• 3. Thus all empirical or existential claims may
  be false, and natural philosophy (science) may
  have no firm foundation.
• 4. Reinforced by hyperbolic doubt - the
  hypothesis of a malign demon, leading to
  skepticism and solipsism.
• 5. But in order to think and to have the doubt,
  he must be thinking and therefore he must exist
  (je pense, donc je suis or cogito ergo sum,
  I think, therefore I am). The one existential
  truth that can be known with certainty.
• 6. Proof of the existence of God I exist
  therefore God exists.
• 7. God is a supreme being and does not (cannot)
  be a deceiver. Therefore, it is possible to have
  a reasonable confidence in the evidence provided
  by sense experience all the things we conceive
  very clearly and distinctly are true.

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The Meditations

• First Meditation
• distinction between natural and mathematical
  sciences (between corrigible and incorrigible
  claims)
• hypothesis of the evil demon or malign genie.
• Second Meditation
• I think, therefore I am.
• Third Meditation
• proof of the existence of God which halts
  infinite regress of skepticism
• Fourth Meditation
• God as the author of clear and distinct ideas
• Sixth Meditation
• Mind-Body dualism

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Gods role in the argument

• Divine veracity guarantees the objectivity of our
  clear and distinct ideas of the things in the
  empirical, material world.
• We can therefore construct physics and
  metaphysics by logical deduction from a number of
  innate ideas implanted in our minds by God.
  Clear and distinct ideas are innate. All
  scientific knowledge is knowledge of, or derived
  by means of, innate ideas.
• Argument
• God is perfect. He cannot, therefore, have been
  involved in deception. Hence, what we see
  clearly and distinctly must be true.
• But
• Has Descartes created a vicious circle by using
  the criterion which is to be guaranteed by the
  proof of Gods existence? Gods existence is a
  precondition for the utility of clarity and
  distinctiveness but is not the proof for the
  existence of God dependant on clear and distinct
  ideas as a criterion for truth?

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Cartesian Dualism

• The world is composed of two kinds of
  incompatible substance mind or consciousness
  (res cogitans) and matter (res extensa). There
  is the mind or the soul on the one hand, and the
  body on the other.
• Mind is unextended and indivisible matter is
  extended and divisible.
• Thus, I am not my body but the consciousness
  inhabiting my body I am the ghost in the
  machine.
• The I is defined, moreover, as consciousness I
  am my consciousness.

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Rules of Method

• 1. Intuition the pure light of reason rather
  than the evidence of the senses or of the
  imagination.
• 2. Analysis the decomposition of complex
  problems into their simple components.
• 3. Synthesis the reintegration, or ordering, of
  truths discovered by steps 1 2, moving from the
  simpler to the more complex.
• 4. Deduction the seeking to perceive an
  immediate link between the first principles and
  their ultimate consequences.
• Method will be a success because the external
  world is mathematical in its structure - matter
  is treated as geometrical extension.