15. Plato’s theory of ideas: the ideal state

• In his theory of ideas, Plato sought to resolve a dichotomy that vexed the Greek mind, the opposition between Change and Being.

• He said that the world we experience, the world of change, the world of sense experience and impressions is only an imperfect outcropping, a shadow of the pristine, unchanging, universal World of forms, that is World of Ideas.

• That world, not this, is the real world. In it are conatined the ideal forms of everything. The world of Ideas is eternal, the world of sensual objects is temporary and illusory.

16. Aristotle: syllogisms

• Aristotle’s logic was founded on the syllogism , in which, given two premises a certain conclusion necessarily follows, for instance:

• “All trees are made of wood, an oak is a tree, all oaks are made of wood (A is B, C is A, C is B)..

17. Hylomorphism: substance and its components

• In general, then, matter is closely connected to potential or power; the potential or power to become some particular sort of thing.

• Only by giving it form can it be made actual (i.e., made into an actual object of a particular kind).

• This portion of Aristotle's metaphysics is called hylomorphism, because it is the claim that all objects are a combination of matter (hulê⁶) and form (morphê)

• Aristotle believed that his hylomorphic theory answered the problem of change posed by Parmenides.

• Parmenides believed change to be impossible because it implies that something passes into nothing, and something else passes out of nothing. Since the "nothing" was thought not to exist, Parmenides concluded that all change is impossible.

• Aristotle's reply is that the basic matter remains the same underneath all change. Only new forms are put in the place of old forms. For example, a block of stone becomes a statue of Pericles because the block-form is removed and replaced with a Pericles-form by the sculptor.

18. Aristotle: the four causes: what is the sence of final cause?

• The idea of potentiality is connected to Aristotle’s theory of the four causes of things.

• Every substance can be described by four causes:

• 1. material (matter),

• 2. formal (form),

• 3.efficient (action)

• 4 final.

• The efficient cause of something is the motion that brings it to its final cause – what it was intended to be.

• Tracing efficient cause back to its source Aristotle concluded that the chain of causes cannot go back ad ifinitum (infinitely, endlessly) therefore there must be a Prime Mover, an “uncaused cause” that is pure form and wholly actualised, namely God.

19. Aristotle: the theory of virtue (Golden Mean)

• But how can we be sure what is best for us that is, was is virtuous?

• the answer to this is one of Aristotle’s brightest ideas and it is known as the famous principle of the Golden Mean;

• virtue, informed by reason lies in the middle between two extremes that is two opposite vices, one of excess and the other of deficiency.

• For example: what does it mean to be brave, what is courage as a virtue – it lies right in the middle between cowardice and recklessness: being a coward is not enough, being a reckless person, showing too much courage is not only unnecessary but also too much (and usually stupid).

• Gentleness lies right in the middle between submission and quick temper (hastiness).