Plato & Aristotle C/B grade summary notes


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Plato’s rationalism: theory of forms & Allegory of cave

  • Rationalism is the view that knowledge can only be gained a priori (from pure logic) – it cannot be gained a posteriori (from experience).
  • The cave illustrates the theory of forms. Prisoners trapped in a cave all their life – they think shadows they see on the wall are the real world. One day a prisoner escapes (philosopher) and sees the actual real world.
  • This is an illustration of the world of forms.
  • We think the world we see is the real world, but it isn’t (that’s why we can’t gain knowledge from experience).
  • The true world is the world of forms.
  • Perfect, eternal and unchanging forms of the everyday things we experience.

Aristotle’s rejection of Plato’s rationalism

  • Aristotle disagrees, he argues we can gain knowledge from experience (empiricism).
  • Aristotle was part of the start of science, which these days has obviously been successful.

The hierarchy of forms & form of the good

  • Part of Plato’s rationalism and view of reality is the theory of forms, which includes a hierarchy in it.
  • The form of the good is illustrated by Plato in the analogy of the cave by the sun. It is the first thing the escaped prisoner (philosopher) sees. The form of the good is like the sun in that it allows us to see the world of the forms and is responsible for all the existence of life and the other forms. This makes it the highest form.
  • Anyone who understands the form of the good makes it impossible for you to do wrong and so a philosopher with this understanding should be called a ‘philosopher king’. 

Aristotle’s rejection of Plato’s form of the good

  • Aristotle rejects this idea – claiming that it’s possible to know what is good but fail to do it.
  • Doing good is not just a matter of know what is good – you also need to be a good person.

Aristotle’s four causes

  • The four causes are a way to understand the change which we experience in the world – they are a way to gain knowledge from experience (empiricism).
  • Material – what a thing is made of. E.g. for a chair, wood or plastic etc.
  • Formal – a thing’s essence or defining characteristic. E.g. for a chair, it’s shape.
  • Efficient – whatever/whoever made the thing. E.g. for a chair, a carpenter or factory worker.
  • Final – the things’ purpose (telos) e.g. for a chair – to be sat on.

Modern science’s rejection of telos/purpose

  • Modern science would accept the idea of material and efficient causation.
  • It would reject final causation, however. 
  • Modern science claims the world is just material atoms in fields of force like gravity which exert efficient causation on each other.
  • There is no such thing as purpose in reality.
  • We might give things purpose in our mind – but that doesn’t mean it actually has purpose in reality.

Aristotle’s prime mover and how it follows from the four causes

  • Aristotle’s theory of the prime mover comes from his theory of the four causes.
  • Aristotle noticed that motion runs out – if you roll a ball, it will stop.
  • The stars and planets have not stopped moving, however.
  • So, there must be a prime mover causing the motion that we experience in the world to continue.
  • This prime mover is a pure mind which eternally thinks about itself and never changes.
  • It causes motion by things in the world being attracted to it.
  • It is the final cause of the universe – the end towards which all things are attracted and thus move.

Newton’s rejection of Aristotle’s basis for the prime mover

  • Modern science since Newton knows Aristotle is wrong about this.
  • If you throw a ball in space – it will just keep going, because there’s no friction.
  • So, Aristotle was wrong to think motion runs out. It just gets transferred into a different type of energy.
  • So, there is no need for the prime mover.