ancient philosophical influences

• Heraclitus


  Ancient Greek Philosopher who thought the world is in a constant state of change ('flux')
• Heraclitus famously said that a person never steps in the same river twice, since both the river and the person change
• Plato's interpretation of Heraclitus


  Presenting a challenge to the possibility of gaining knowledge, since everything is constantly changing
• Plato's conclusion


  True eternal unchanging knowledge cannot be gained empirically, so we must look to a priori reason alone
• Aristotle's view


  We can understand the causal mechanism responsible for change and thereby gain true knowledge from experience
• Plato's rationalism

  • True reality must be perfect, eternal and unchanging (the world of forms)
  • True knowledge can only be gained from the world of forms
• Plato's allegory of the cave

  Prisoners (us) in a cave (our reality) perceiving shadows (the objects we experience) of real objects, which are the true forms
• Plato rejects empirical evidence because it cannot be trusted, as it is merely shadows of the real world of forms
• Aristotle's four causes


  • Material cause (what something is made of)
  • Formal cause (the essence or defining characteristic)
  • Efficient cause (what brings it into existence)
  • Final cause/telos (the end goal or purpose)
• Aristotle thought all change in the universe can be explained by the four causes
• Plato's argument from recollection


  We have knowledge of perfect, eternal and unchanging concepts, which we must have gained before birth, implying the existence of a soul and a world of forms
• Prime mover


  The unmoved mover and the final cause of the universe. It is not the efficient cause of the universe, since Aristotle believed the universe was eternal. The Prime Mover is responsible for the everlasting motion and change of the universe. Since it cannot be moved, it cannot change and is thus pure actuality
• The way the prime mover sustains the change in the world must be due to some sort of attraction of the things in this world to it