Rationalism Flashcards
key ideas
- a priori
- innate
- mathematical knowledge is innate - exists objectively but we understand it through reason
- A priori knowledge deductive
- empirical knowledge inferior
plato beliefs
- sense experience can trick us - allegory of the cave
- things constantly changing in physical world
- all we know is incomplete, imperfect reflection of the absolute and unchanging version of things - FORMS
- dualist: soul separate from bodies.. soul encountered realm of forms before entering body
- must look inwards to soul … we recollect things do not learn! LEARNING IS RECOLLECTING
- soul is source of rationality because it experienced the realm
plato strengths
strengths:
- true that senses mislead us (Descartes)
- explains why some people better at things than others…people that are better at maths use rationality to recollect better.
- perfection: no one has seen perfect circle, yet everyone knows what the concept of one is. Must be innate knowledge.
plato weaknesses
- Aristotle argues that the body and soul require each other.. thus the body must have gone with the soul to the realm of the forms. Illogical: we aren’t recollecting from the realm.
- maths can be learnt: may be unchanging, but we can learn it.
descartes (skeptic) overview
- senses misleading and unreliable
- must use reason to find truth
- illusion example: Müller-Lyer illusion - one line may look longer than the other even if they are the same length
descartes wax argument
- characteristics of wax change when melted
- wax remains same object but sensory qualities different and therefore cannot be the essence of the wax
- reason necessary in order to perceive and understand changing nature of the wax
“the search for truth and knowledge involves the search for certainty”
descartes - Cartesian doubt
barrel of apples
anything which could be doubted must be searched in order to find what is known
the need “to demolish everything completely and start again right from the foundations” - Radical Skepticism
Analology of Barrel of Apples:
- to remove bad apples, ed to first empty barrel in order to be 100% sure
- we should take out every idea we know to be true and set aside ideas which a reasonable doubt could be entertained in the same way
- thus we can find rock foundations
Descartes - 3 waves of doubt
- Illusion: senses deceive us…eg two men same height look different because of perspective
- Dreams: how do we know that we are not dreaming?
“There are no conclusive signs of which one can distinguish clearly between being awake and being asleep.”
- some dreams can be indistinguishable from waking life, and thus through this skeptical hypothesis, we cannot trust our senses in waking life (as we do not even know if we are dreaming). - Deception/Evil Demon: deceives us of everything - thus none of our experiences are real because there is no proof.
Descartes believes that…. is absolutely certain
- I know I am thinking
- “cogito ergo sum” - I think therefore I am
- minds are filled with intellectual innate concepts (from God)
- knowledge of ourselves/ God/maths/logic etc.
Descartes weaknesses
- 2nd wave
- pragmatism
- Weittengenstein
- Relies on the belief and existence of God - without Him, theory fails
- 2nd wave of doubt:
- dreaming requires state of dreaming to exist.. can’t be always dreaming
- PRAGMATISM: “ignorance is bliss” - we should not doubt things that seem intuitively true. If we do, then we will fall into an infinite state of question and mental illness. Thus, we must begin ‘in media res’ - in the middle of things - and confess that are starting-points are contingent and conditioned by history. - Wittengenstein: skepticism lacks a proper sense of what counts as doubt
- philosophers who doubt whether motorcars do not grow from trees are bordering on insanity.
Descartes weaknesses - Putnam
LOOK UP IN HALF TERM
Descartes main arguments
- skeptic
- cannot trust senses (candle wax)
- must doubt everything er think we know
- “I think therefore I am”
- innate ideas in mind; must reason to access them
- rationalist
Spinoza’s ideas
- use reason to organize sense perceptions
- no essential basis in sensory experience
substance: something which does not require the idea of any other thing in order to be understood
God/nature:
- God gives us our understanding
- Pantheism: God was nature
- to understand nature is to understand God because God is present everywhere
Leiniz’s ideas
- use of reason to understand the world
- ideas are innate and immaterial: cannot be caused by material activity (sensory)
- universe made up of monads: simple, ordinary and rational souls.
- only rational souls have apperception: this allows for the ability to know necessary and eternal truths about the universe and God.
Nagel’s ideas (modern)
- our ability to know is limited by our perspective BUT we have the ability to develop appropriate hypothesis about the world independent of our viewpoint e.g. animals grow up without mother yet have biological instinct to run away from predators…. innate knowledge?
- humans can “conceive world as a whole”
- thought allows humans to extend beyond our local experiences
