as above

1. Cartesian Rationalism:
The Cogito
Meditation 2 and onward…

2. Putting the Demon back in its Bottle
• Successful method?
– is Descartes’ method of doubt a useful and
thorough tool to eliminate uncertain beliefs?
– …or a useless project that takes doubt too far and
out of context?
– …it may rule out the possibility of error…
– …but is any of our knowledge rescuable?
• Descartes’ difficulty:
– unless he can find infallible foundations for
knowledge, infallibilism will lead only to
scepticism…
– Goldman: ‘A major task…is to show that there is
some such set of self-warranting propositions that
support external-world propositions.’

3. The Cogito Cogitated
‘this proposition, I am, I exist, must be true
whenever I assert it or think it.’
• Can you conceive of any difficulties here?
– Any qualifications?
– Any undefined terms?
– If you can think of difficulties, what follows for
infallibilism?

4. Descartes’ First Certainty: The Cogito
• the Evil Demon argument cannot generate doubt
about my own existence or the fact that I am thinking.
– …Not even an all-powerful evil genius can make me think that I
exist when I do not exist.
– This would require making me exist and not exist at the same
time, which is impossible.
– And not even an all-powerful evil genius can make me think that
I am thinking when I am not thinking.
– This would require making me think and not think at the same
time, which is impossible.

5. The Cogito: a ‘self-warranting
proposition’
• Formulations:
– Cogito ergo sum – first (Latin) version of ‘The Meditations’
– I think therefore I am – English translation of the Latin
– ‘I am, I exist, must be true, whenever I utter or conceive it in my
mind’ – English translation of first French version.
• Descartes suggests the latter (in another text):
• “When someone says “I am thinking therefore I am, or I exist”,
he…recognises it as something self-evident by a simple intuition
of the mind.”
• So, Descartes intends the Cogito to be a self-verifying act of
intellectual intuition: Its truth becomes apparent through the act
of performing it: ‘I am thinking, therefore I exist.’
• It is often called his ‘First Certainty’ for this reason.

6. Issue 1 Issue 2
Issue 3 Issue 4

7. Issues with Descartes’ intellectual intuition:
if true, time-limited
• The Cogito is a very limited
proof: ‘I am, I exist, must be true,
whenever I utter or conceive it in
my mind’.
• …you only exist for as long as
you are performing the Cogito?
•  ‘It will be true only if I think it
and only so long as I think it.’
• So, the proof of self-existence
expressed by the cogito is
temporary…
– But Descartes thinks that even a
single moment is enough…
Existence only in the gaps between ?words?
Rene Magritte, ‘The Blank Chart’, 1961

8. Issues with Descartes’ intellectual intuition:
Lichtenberg, grammar, absence of self
• Deep vs surface grammar: e.g. most nouns are
(proper) nouns, and label things. What do
abstract nouns label?
• Not all nouns refer to actual objects…
• Compare
– ‘Eric runs’ – there is a subject, running.
– ‘It rains’ – is there a subject, raining?
– ‘Eric thinks’ – there is a subject, thinking.
– ‘I think’ – is there a subject, thinking?
• Georg Lichtenberg (C18 physicist, aphorist): ‘“It
thinks”, we really ought to say, just as we say, “It
thunders”’.
• We assume the sentence ‘I think’ has a
subject…does it?
mouse – an actual object
mousiness – not an
actual object

9. Issues with Descartes’ intellectual intuition:
(The underlying picture of) the Cartesian Theatre is weird

10. Issues with Descartes’intellectual intuition:
Humean bundles, limited selves
• Can Descartes claim that he has an immediate,
unmediated, non-inferential perception of himself?
• In opposition to Descartes, David Hume says that
whenever he tries to perform the Cogito, he has no
certain consciousness of himself…
– “For my part, when I enter most intimately into
what I call myself I always stumble on some
particular perception or other, heat or cold, light
or shade, love or hatred, pain or pleasure. I never
can catch myself at any time without a perception,
and never can observe anything but the
perception.” (Treatise, I,iv,6)
• For Hume…the self is just a bundle of sensations
• You are merely…a collection of thoughts

11. Intellectual intuitions summarised…
• Descartes (arguably) thinks that the Cogito is a moment
of pure a priori intuition or demonstration…
– His ‘Archimedean Point’
– The foundational, non-inferential justification-condition which
allows a key knowledge-claim to be made…
– Because of the Cogito, fundamental claims about what
exists/can be known can be grounded in and justified by infallible
a priori intuition and/or demonstration.
– And through further steps based on the Cogito, Methodological
Doubt can be arrested and the Evil Demon and Dream
arguments defeated
• Key problems with the Cogito remain, even if true:
– Arguably it is a proof only of flashes of self-existence
– Arguably it does not prove the existence of a classically
conceived self or ego

12. Next steps: Clear and Distinct Ideas
• Even if the Cogito is only performed for an instant it is
indubitably true whilst it is being performed.
• It is a ‘clear and distinct idea’:
– “I call 'clear' that perception which is present and manifest to an
attentive mind…”
– I call 'distinct', that perception which, while clear, is so separated
and delineated from all others that it contains absolutely nothing
except what is clear“.
– “If we give assent only to those things which we clearly and
distinctly perceive, we will never accept anything false as being
true…”.
• So: C&D = T!

13. Next steps: The Trademark Argument
• Another clear and distinct idea (=rational intuition) we
have is that of God
– We have the idea of God within us
– He has placed his ‘trademark’ on us.
• Ideas are copies of originals which are greater still. And
a trademark implies a maker.
– So God must exist, to have originated the idea of him / to have
placed his trademark.
• And God is not a deceiver: so anything we perceive
clearly and distinctly is true.
• So we can trust our senses if we check our sensory
experience using our rational intellect…

14. Brief paired writing tasks
1. Explain Descartes’ Cogito argument
2. What issues with his conception of self
are there?
3. What characterises Clear and Distinct
ideas?

15. Descartes’ Reconstruction of Knowledge
1. I can only know what is infallibly justified and therefore true.
2. Cogito is true. What qualities does it have?
3. [Clear and Distinct Ideas] The Cogito is a clear and distinct idea,
which means it is true (as it is guaranteed by God, whom I perceive
C&D to exist).
4. What other ideas are clear and distinct ( = true) within me?
5. [Trademark Argument]…The idea of God is clear and distinct within
me, and this idea is so perfect I cannot have placed it there, so it
must have come from God.
6. Hence God exists and is not a deceiver.
7. Thus the Evil Demon and Dreaming Arguments are not correct.
8. And many of my perceptions of everyday objects are clear, and
when they are known through intellectual judgement also, they can
be distinct.
9. Hence as long as I am careful to judge my sensory evidence
rationally I can trust the evidence of my senses and avoid Error
and Illusion