Descartes- mostly med 3
• The challenge gacendi put for Descartes is give me a method from which I can tell that
something is clear and distinct.
• His answer is that I have already did that, the question is where did he do that?
• The answer is in mediation 1
• Descartes say if you can doubt an Idea or a plain then there is something wrong with it.
There is a defect in it.
• The conclusion is that any ideas which are acceptable than it must be clear and distinct.
• He tells gancendi if something can be doubted than it is not acceptable
• Therefore using conversion you make the antecedent to the consequent and antecedent
to the consequent and add a telda.
• The logic of meditation one is that Descartes points out if something is acceptable it is
• Although truth has one of its feature being indubitable that isn’t all it is, because
indubitable is a necessary condition. It’s not the only feature because
• I think therefore is am is for Descartes is true, like the I think therefore I am, mathematics
is also clear and distinct but Descartes says that mathematics can be doubted when you
take in to account that God was trying to deceive me.
• If god wants to deceive me he can deceive me with mathematics
• When you think a mathematical proposition such as 1+1=2 you cannot doubt it. When
you are thinking mathematical you cannot doubt it. When you think about mathematics
you bring God in the context therefore you doubt it. (59)
• Mathematics is view in two different ways.
• In terms of all decartes has to say “ I think therefore I am” is never ever doubted. It has a
prilieveged status, not even God an deceive us with respect to “ I think there fore I am “
pg 41 course kit) replies 2.
• Although mathematical claims are indoubtablie when you think of them once you
introduce the though of God you can easily see the mathematics is true.
• Not even God can deceive us of “ I THINK THEREFORE I AM” • In meditation four there must be a proof using “ I think therefore Iam “ that there is
• Constructed reply to gancende:
• 1) Official reply to gacende (213-14 CK) – he tells gancende he answered his concern in
med 1 beyond med 1 he is only dealing with clear and distinct ideas.
• 2) claim that the denial of clear and distinct ideas are self contradictory is false (princlple
7 page 60)
• What is self contradictory is the denial of clear and distinct ideas
• What is the denial of I think there for I am? It would I think therefore I do not exist.
• Thinking of though and not thinking of evidence is contradictory
• 3) Principle 7, decartes is saying finding the denial of I think therefore I am is all you
need to prove its true
• However in the case of mathematics it is equally true that the denial of a true
mathematical propostion is self contradictory. There is the same contradiction in
mathematical claim and I think therefore I am.
• The knowledge of God I essential to establish the truth of mathematics
• 4) med 4
• Decartes claim in the reply to gacendi stage 2 for clear and distinct
• Step 1. There is a physiological irresistibility (pg 81) (84)
• Step 2. Principle 10 (222) pg 14 med – the thought of though and the thought of
existence are separate thoughts
• Step 3) A J lyer said that that the claim I think therefore I exist is not self contradictory
• Stept 4) there are some sentences that can be shown to be true by reviling that there
denial is self contradictory
• How to do that? Example
• All bachelors are unmarried males
• All bachelors are happy