Descartes and Epistemology Flashcards
Descartes distinction between a priori intuition and deduction?
Intuitions - those truths known immediately, just by thinking about them
Deduction - those truths known by means of reasoning chains.
Descartes’ clear and distinct ideas (relating to the cogito)
Clear - must be known to be true as soon as thought
Distinct - an idea is considered “distinct” when it is clearly separated and delineated from other ideas, not being confused with anything else.
Descartes ‘cogito’ as an example of an a priori intuition
Rationalist claim - some synthetic truths can be known a priori - conceivable clearly and distinctly,
The three waves of doubt - illusion, dreaming, deception, the fact that descartes is able to doubt his own existence proves that he exists,
‘i doubt, therefore i think, therefore i am’
even if the evil demon is trying to deceive him on just about everything, Descartes can not doubt that he exists.
The reason for this is that even if the demon is deceiving him, there must be something for the demon to deceive in the first place!
Descartes a priori deduction - proof of the external world
P1. i perceive the external world with physical objects,
P2. the cause of my perceptions cannot be my mind because they are involuntary,
C1. therefore, the cause of my perceptions must be something external- either god or physical objects,
P3. if the cause is god, then he has created me with a tendency to form false beliefs from my perception,
P4. but god is a perfect being and so would not deceive me into having such false beliefs,
C2. therefore, the cause of my perceptions is not god,
C3. therefore, the cause of my perceptions is an external world with physical objects,
P5. the cause of an effect must have as much reality as its effect,
C4. therefore, the external world exists.
Descartes a priori deduction - existence of God TRADEMARK ARGUMENT
P1. i have a clear and distinct idea of god as an infinite and perfect being,
P2. my ideas are caused by something,
P3. i am a finite and imperfect being, so the cause of my idea of god cannot be myself,
P4. the cause of an effect must have as much reality as its effect,
C1. therefore, the cause of my idea of god must have as much reality as what the idea is about,
C2. therefore, the cause of my idea of god must be an infinite and perfect being,
C3. therefore, god exists.
explain Descartes trademark argument
He has the innate idea or ‘trademark’ of god as a supremely perfect and infinite being and a trademark implies that there is a maker so god must exist to have originated this idea of him within us; because he is a finite and imperfect being, he can only have finite and imperfect ideas on his own and so something infinite and perfect must have planted the idea of such a being in his mind i.e. god
Outline Hume’s objection concerning causality to the trademark argument
P2 (my ideas are caused by something) is not an analytic truth as, although experience suggests that everything has a cause, this is still only a contingent truth considering we cannot show that it holds without exception and is therefore a weak premise to base the rest of the argument on;
also, causation is something that can only be known through experience (a posteriori) as it requires experiencing one thing always coming before another and so any argument regarding causation cannot be a priori thus this fails as an a priori deductive proof;
Descartes’ first premise is a matter of fact claim (he passes it off as intuitive), he thinks he can derive a logical chain of reasonable deduction to prove the existence of God, but the first claim is itself deniable.
COTTINGHAM challenges trademark argument
P3 (no effect can be greater than whatever caused it) novel properties can arise from natural phenomena, contradicts Descartes
eg. cause - eggs, flour, sugar → effect - sponge cake (or gametes fusing = conscious thinking baby)
descartes response - the properties are eminently contained by the cause
Explain Hume’s Fork.
Hume’s fork neatly carves up the world of knowledge into two distinct categories: matters of fact and relations of ideas
Matters of fact seem to all be synthetic/ a posteriori/ contingent - based on sensory experience (eg Trump will be president 2024)
Relations of ideas all seem to be analytic/ a priori/ necessary (eg maths) can be known through reasoning
Response to the cogito - Gassendi, cogito is deduction not intuition
I think,
Thinking things exists,
Therefore, I exist.
(contains a hidden premise - his argument is an enthymeme. Omnipotent deceiver may exist, need to disprove this)
This is thus not a foundational truth, this is a deduction, thus it relies on memory and is not safe from the evil demon
Outline Hume’s fork as an objection to descartes proof of the external world
the existence of the external world is not a relation of ideas because the statement ‘the external world exists’ is not an analytic truth, nor is it matters of fact because we only have our experience of the external world but never experience the cause so we cannot know that there is an external world causing my experiences; the existence of the external world does not fall under either prongs of Hume’s fork and is therefore not a form of knowledge
how does Hume reject to the proof of the external world using causation
causation is something that can only be known through experience (a posteriori) as it requires experiencing one thing always coming before another and so any argument regarding causation cannot be a priori thus this fails as an a priori deductive proof
The synthetic truths Descartes argues
1) I exist,
2) god exists,
3) the external world exists.
challenge to the trademark argument, concept of god is not innate
Rejecting the first premise and arguing that the concept of God is not innate. If the concept of God comes from experience, as Locke argues below, then Descartes’ argument is not entirely a priori and thus fails to establish rationalism.
Further, Descartes’ argument for the existence of the external world relies on his arguments for the existence of God. So, if Descartes’ arguments for God are not a priori, then neither is his argument for the existence of the external world.
So, if Descartes’ arguments rely on a posteriori concepts, then they do not establish synthetic truths a priori and thus fail to prove rationalism is correct.
Response to the cogito - Mersenne objection a priori attack
A priori attack - disputing Descartes’ foundationless position, he is not absolutely certain. His first premise needs justification because you cannot assume that the term ‘I think’ is known so it needs to be defined which then needs scrutiny, and so on - it becomes an infinite regression (series of justifications that never reach an endpoint).
Descartes’ response = intuition. Some things that you have to accept as known in order to have any thoughts at all (appeal to intuitive thoughts claim again). It is ‘pre-reflective’ non-deductive truth that the mind grasps as soon as it exists
