rationalism vs empiricism Flashcards
what is the rationalism vs empiricism debate?
what kind of knowledge we can acquire through a priori intuition and deduction
what is intuition?
the ability to know something is true just by thinking about it
e.g. descartes cogito
what is deduction?
a method of deriving true propositions from other true propositions (using reason)
e.g. deducing statement 3 from statements 1 and 2
1) if a is true then b is true
2) a is true
3) therefore, b is true
what is the difference between empiricism and rationalism?
- empiricism says all a priori knowledge is of analytic truths (i.e. there is no synthetic a priori knowledge)
- rationalism says not all a priori knowledge is of analytic truths (there is at least one synthetic truth that can be known a priori using intuition and deduction)
what are the truths that descartes found through intuition and deduction?
- i exist (cogito)
- god exists
- the external world exists
what does descartes do to have knowledge?
descartes is an infallibalist so he only wants to know if it is certain and so before attempting to establish knowledge, he begins by doubting everything he thinks he knows.
he has three waves of doubt:
- illusion
- dreaming
- deception (evil demon)
what is his illusion wave of doubt?
i can doubt the reliability of my sense experience as it has deceived me in the past
- for example, a pencil in water may look crooked even though it isn’t or from a distance an object might look different to how it actually is.
but this is not a reason to doubt everything - illusions don’t happen that often, and when they do we can generally tell.
- the fact that we are able to recognise illusions as illusions shows that they are weird exceptions to otherwise normal experience
what is his second wave of doubt, dreaming?
i may think i am awake when i am actually dreaming, so i might believe i am looking at a computer screen, but if i am simply dreaming that i am, then that belief is false.
- this is a stronger form of foubt - everything you perceive could be false, because in a dream all your perceptions are imaginary and yet you believe they are real.
however, when you’re dreaming there are still basic ideas that are common to both dreams and reality e.g. size and shape
what is the third wave of doubt?
an evil demon could be controlling my entire experience, making me think 1+1=2 is true when it is actually false
- this means basically everything i think i know can be doubted and i could have only false beliefs
what is philosophical sceptisism?
position of extreme doubt
e.g. evil demon
- in this descartes rules out almost all knowledge - he cannot trust his perceptions and so he has only his mind from which to establish knowledge i.e. intuition and deduction
what is the cogito?
dubito, ergo cogito, ergo sum = i doubt, therefore i think, therefore i am
- his point is that even if the evil demon is decieving him on just about everything, descartes can’t doubt that he exists
- even if the demon is deceiving him, there must be something for the demon to deceive in the first place
- the fact that descartes can even doubt his own existence is proof that he does exist.
what are clear and distinct ideas?
the cogito is a rational intuition which means it is not a matter of deriving the conclusion ‘i exist’ from the premise ‘i think’ but is instead something that the thinker can see is true simply by thinking about it
- something like this that is true using rational intuition is a clear and distinct idea
why can clear and distinct ideas be trusted?
they are so self-evidently true that they cannot logically be doubted
- the fact they can be trusted gives descartes a platform from which he can reason his way out of his position of extreme scepticism
what is the trademark argument?
p1) i have the concept of god
p2) my concept of god is the concept of something infinite and perfect
p3) but i am a finite and imperfect being
p4) the cause of an effect must have at least as much reality as the effect
p5) so, the cause of my concept of god must have as much reality as what the concept is about
p6) so the cause of my idea of god must be an infinite and perfect being
c) so god exists
what is the point of the trademark argument?
descartes’ point if essentially that it’s impossible that he himself could have come up with this concept of god - an infinite and perfect being - all by himself.
- whatever caused descartes’ idea of god must itself be an infinite and perfect being because descartes argues, the causes of an effect has as muchreality as the effect
what type of truth is god exists?
a synthetic truth and descartes has seemingly established it using intuitoin and deduction only.
what is descartes’ argument for the existence of the external world?
p1) i have perceptions of an external world with physical objects
p2) my perceptions cannot be caused by my own mind because they are involuntary
p3) so the cause of my perceptions must be something external to my mind
p4) god exists
p5) if the cause of my perceptions is god and not the physical objects themselves, then god has created me with a tendency to form false beliefs from my perceptions
p6) but god is a perfect being by definition and so would not create me with a tendency to form false beliefs from my perceptions
p7) so i can trust my perceptions
c) so given premises 1 and 7 above, i can know that an external word of physical objects exist
what is the overview of descartes’ argument for the existence of the external world?
because god exists, his perception can be trusted. these perceptions are of an external world of physical objects, and because descartes can trust his perceptions, he can trust the external world exists
what truth is the external world exists?
this is a synthetic truth as there is no logical contradiction in the idea of the world never existing
- his reasoning here is a priori: he can’t use his perceptions to prove the external world exists because the evil demon argument ruled that out earlier but he uses reasoning outside of perceptionto show that his perceptions can be trusted and that the external world exists
what are relations of ideas?
cannot be denied without contradiction
- either intuitively or demonstratively certain
- discoverable by the mere operation of thought, without dependence on what is anywhere existent in the universe ( a priori)
what are matters of fact?
there is no logical contradiction in it being false
- contrary of every matter of fact is still possible; because it can never imply a contradiction
- can’t be established purely by thought and thus require empirical observation to establish their truth
what is the key difference between a relation of ideas and a matter of fact?
the denial of a matter of fact is possible, but the denial of a relation of ideas is impossible
- grass is green is true as a matter of fact because it’s logically possible for this to be false
- it is logically impossible to deny a relation of ideas such as triangles have 3 sides
what is hume’s fork?
hume’s fork is the claim that there are only two kinds of knowledge: relations of ideas and matters of fact
how can we apply hume’s fork to descartes’ arguments?
we can argue that they rely on matters of fact, but according to hume’s fork matters of fact are a posteriori.
- if humes fork is correct, then it shows the descartes’ arguments are not entirely a priori and thus fail to establish rationalism
what is a response to the cogito?
descartes concludes ‘i exist’ from ‘i think’ but hume argues that this doesn’t necessarily follow
- hume points out that what we actually experience is a constantly changing array of thoughts and perceptions but we actually never experience a SELF
- there are thoughts but this does not guarantee that there is a constant thing that actually thinks those thoughts, or that this thing is the same thing from one thought to the next
there is no logical contradiction in the idea of a thought without a thinker and so you cannot deduce ‘i exist’ from ‘i think’ using a priori reasoning only
what is the causation requires experience objection?
the trademark and cosmological arguments rely on a premise that is something like everything has a cause or every cause must have at least as much reality as the effect. however, if we show that knowledge of causation requires experience, then we show that these arguments are not a priori and thus fail to establish rationalism
how can the causation requiring experience be shown?
we can argue that the premise everything has a cause can be denied without contradiction
- it’s a weird idea, but there is no logical contradiction in the idea of an uncaused event
- so applying hume’s fork we can argue that this shows ‘everything has a cause’ is a matter of fact rather than a relation of ideas
- and all matters of fact require empirical experience
what is the argument that the concept of god comes from experience?
in his trademark argument, he claims that his concept of god cannot come from experience and must be innate, however if we can show this concept does come from experience, then we show that descartes’ argument is not a priori and thus fails to establish rationalism
how does hume respond to descartes’ claim that he cannot come up with the idea of finiteness?
hume disagrees that we could not come up with the concept of god and he argues that we can create concepts such as infinity and perfection by taking the finite and imperfect ideas we get from experience and extending these beyond all limits
- experience gives us the concept of goodness and so to create the concept of a perfectly good being (god)
what is the objection of descartes’ argument for the external world?
his proof of the external world relies on the premise that god exists and that god is the cause of his perceptions. but if we can cast doubt on descartes’ arguments for these claims and whether they are a priori then we can cast doubt on his argument for the existence of the external world
what is the objection of causation?
descartes’ proof of the external world relies on knowledge of causation
- he argues that because his perceptions are involuntary they must be caused by something external to his mind
knowledge of causation requires experience. hume would say there is no logical contradiction in the idea of a perception that has no cause and os we cannot know a priori that our perceptions are caused by something external
