1. History of Philosophy

2. The foundations of Western metaphysics: Plato and Aristotle

3. Plato (c. 429-347 BC) Knowledge and opinion, their methods and objects according to Plato
shadows & reflections
living creatures, works of nature or of human hands
numbers & geometrical objects
ideas
imagination
eikasia
belief
pistis
mathematical investigations
hypothetical method
dianoia
philosophical understanding
dialectic method
noēsis
opinion (doxa)
knowledge (epistēmē)

4. Do not enter, if you don’t know geometry (= mathematics)!
Plato followed some teachings of Parmenides, Heraclitus, Socrates, Pythagoras and Pythagoreans and organisation of their community. Mathematics was a necessary condition and preparatory stage of philosophical studies in his famous school called Academy (of Athens), located in his own grove dedicated to a hero Akademos.
Legend had that above the entrance to the grove there had been an inscription saying:
Do not enter, if you don’t know geometry (= mathematics)!
Plato wrote more than 40 dialogues, e.g., Apology, Republic, Euthyphro, Laws.

5. The highest level of knowledge allows to know forms (ideas) – they are not only general concepts (universals), but also real entities, independent, divine, invisible and changeless, like Being of Parmenides. For Plato to know something, to have knowledge of it (true by definition) meant to apprehend intellectually forms (ideas), and because knowledge to be true cannot change, objects of knowledge must not change either.

6. To make his point even stronger Plato decided that these objects are not just universal concepts, which might have been products of mental processes but they are universal and real objects. The form (idea) of Good is unique and is on the top of the hierarchy of other forms (ideas). Apprehension of this form is mystical. The highest form of knowledge is not rational, intellectual, but mystical. It is the end of the philosophical journey, the end of intellectual and moral itinerary and evolution. To know truth is to change dramatically one’s life (metanoia) and prepare oneself to the afterlife.

7. Metaphor of the Cave

8. The physical world was produced by the demiurge of eternal primary matter. Physical objects are copies of forms (ideas).  ideal  copy (sth that imitates an ideal but is not prefect) Forms are causes of physical objects. Therefore realistic art (sculpture, painting etc.), which for Plato was the copying of copies, was of minor value.

9. Critique of the Theory of Forms - The Third Man argument
Plato himself criticised his theory of forms. Suppose we have a set of large things. They are large, because they participate in the form of largeness. The large things and the form of largeness are united in one class, and there must be a further form of largeness, which puts together all members of this class. If so, there must be a further form of largeness, which unites the 2nd level form of largeness, and the 1st level form of largeness plus large things, and so on ad infinitum.
Aristotle used the example of men, which gave the name to the argument.

10. Aristotle ( B.C.), a disciple of Plato, and a teacher of Alexander the Great, was 17 when joined Plato’s Academy and remained there until Plato’s death. After a period of travelling he came back to Athens and set up his own philosophical school – Lyceum in a grove sacred to Apollo Lyceus (Greek: Lykaios, ‘the wolf-god’). His disciples were called Peripatetics after the peripatos - covered walk or peripatein – to walk, to stroll. Aristotle’s dialogues – now lost. Corpus of his treatises: logical works, works on physics, ‘the study of things that are’ - the Metaphysics (the name given by Andronicus of Rhodes (1st c. BC), ta meta ta physika - books after those on physics), psychology and natural history, ethics.

11. Aristotle criticised Plato’s theory of forms along Plato’s lines.
He himself put forward a less radical theory of individual objects and their universal qualities.
There are only individual objects, but they have certain qualities, wchich are essential for them, their essence or form consists of them. Universal or general concepts and names are mental and linguistic counterparts of essences/forms/natures of sets of individual objects.
A word ’dog’:
in mind – a concept, general meaning (intension)
outside mind - a set of objects described by a
predicate (predicates) in a definition of a concept.
The extension of ’dog’ is the class of dogs.

12. Form and matter, actual and potential, substance and accident – concepts necessary to explain affinities among individual physical objects, their emergence and decay. Four causes: formal, material, efficient, final.

13. Men are able to know, because they are informed by their senses
Men are able to know, because they are informed by their senses. Human reason is able to abstract universal qualities of sensory objects, by analysing sensory perceptions, and these universal qualities form universal concepts. Individual objects of the sensory perception have a set of unchangeable qualities – a form, which is grasped in universal concepts. Forms make objects what they are, i.e., members of a class: birds, plates, human beings, etc.

14. The sensory experience is the beginning of knowledge but it must be rationally justified by syllogistic logic. Syllogism – the inference of one proposition from two premises (propositions). Example:
propositions
All men are mortal.
major premise
major term
Socrates is a man.
minor premise
minor (middle ) term
Socrates is mortal.
conclusion

15. Correspondence theory of truth
Aristotle's definition of truth (Metaphysics 1011b25):
“To say of what is that it is not, or of what is not that it is, is false, while to say of what is that it is, and of what is not that it is not, is true”.
Almost the same formulations can be found in Plato.
In general truth consists in a relation to reality, i.e., truth is a relational property involving a characteristic relation (to be specified) to some portion of reality (to be specified). (Stanford Encyclopedia of Philosophy - SEP)