Aristotle on Knowledge Aristotle 384 322 BC n

Aristotle on Knowledge

Aristotle 384 -322 BC n Student of Plato (429 -327) n Teacher of Alexander (353 -323) n Founded ‘Lyceum’ n We have his lecture notes n Posterior Analytics n Metaphysics n

Forms n Aristotle rejected Plato’s theory of Forms n ‘Third Man’ argument n We recognise Bob as a man because he participates in the Form of Man n We recognise the Form of Man as the Form of Bob because both have something in common n Both participate in a further Form of Man – the Third man. n We recognise the Third Man as a Form of Man because of a Fourth Man …

Forms n Aristotle rejected Plato’s theory of Forms n Forms can’t explain change n. A thing which is small may become large n It began participating in Small n It ends by participating in Large n How?

Forms and Matter n Aristotle had a theory of Forms are the patterns of existing things n Forms impose a pattern on Matter n n Duck, daisy, dish – same matter, different form The two exist together – they are only logically distinct n Matter and Form constitute Substances – the basic things in the world n

Substances are things that have properties n Aristotle lists ‘categories’, or kinds of property. n n n Quantity, quality, relation, location, time, position, habit, action, passion Change can now be understood n Substance takes on new properties n Socrates n was sad but becomes happy Material of Substance takes on new Forms

Causes n Aristotle proposes 4 type of cause 1. Material The statue is brown because it is bronze 2. Formal The statue has legs because it is the image of a man 3. Effective The statue looks like a man because the bronze was poured into a man-shaped mould 4. Final The statue was made because it honours Pericles

Explanations n These ‘causes’ are really kinds of explanations n They are answers to the question ‘Why is S a P? ’ n Why is the statue brown? (Why is it a brown thing? ) n Why is the moon eclipsed? n Why is the child ugly? n Why go walking?

Explanations n What explains why S is P? n Look at the standard ‘syllogism’ in his Logic Socrates is a Man All Men are Persons Socrates is a Person This justifies believing that Socrates is a Person n It also explains why Socrates is a Person (S is P) n

Explanations n Take any argument of the form S is M M is P S is P We can say: Why is S a P? Because S is M and M is P n To find an explanation we just need to find the right M (called the Middle Term) to go between S and P n

Explanations n So: Why is the Statue Brown? We have: Statue is M M is Brown Statue is Brown

Explanations n So: Why is the Statue Brown? We have: Statue is Bronze is Brown Statue is Brown n The reason is, because the Statue is Bronze and Bronze is Brown

Explanations n Similarly for the other questions Why is the moon eclipsed? n Because it is darkened by earth’s shadow, and to be darkened by Earth’s shadow is to be eclipsed n That is the formal cause n

Explanations n Similarly for the other questions Why is the child ugly? n Because the father is ugly and ugly fathers have ugly children n That is the efficient cause n

Explanations n Similarly for the other questions Why go walking? n Because those who want to be healthy go walking, and we want to be healthy n That is the final cause n

Scientific Knowledge n Episteme is a collection of such deductions We suppose ourselves to possess unqualified scientific knowledge of a thing, as opposed to knowing it in the accidental way in which the sophist knows, when we think that we know the cause on which the fact depends, as the cause of that fact and of no other, and, further, that the fact could not be other than it is (Post. An. 1. 2)

Scientific Knowledge n ‘the cause of that fact and of no other’ Statue is Bronze is Brown Statue is Brown n Given the first two premises only the conclusion follows, and no other

Scientific Knowledge n ‘the fact could not be other than it is’ Statue is Bronze is Brown Statue is Brown n Given the first two premises the conclusion could not be other than it is (validity)

Scientific Knowledge n Episteme requires conditions on such deductions the premises of demonstrated knowledge must be true, primary, immediate, better known than and prior to the conclusion, which is further related to them as effect to cause n n Deduction with these conditions is Demonstration (Apodeixis) Demonstration thus excludes trivial or irrelevant deductions

Scientific Knowledge n ‘the premises of demonstrated knowledge must be true’ n False premises make a syllogism unsound All men are vegetables All vegetables are mortal All men are mortal n This syllogism doesn’t give us knowledge

Scientific Knowledge n ‘the premises of demonstrated knowledge must be better known than and prior to the conclusion’ There is a difference between what is prior and better known in the order of being and what is prior and better known to man. I mean that objects nearer to sense are prior and better known to man; objects without qualification prior and better known are those further from sense. Now the most universal causes are furthest from sense and particular causes are nearest to sense, and they are thus exactly opposed to one another

Scientific Knowledge n ‘the premises of demonstrated knowledge must be better known than and prior to the conclusion’ n Things may be known immediately to our senses n That n triangular patch of grass is green Such things are not certain or universal or eternal

Scientific Knowledge n ‘the premises of demonstrated knowledge must be better known than and prior to the conclusion’ n Other things may be known less immediately n The n internal angles of a triangle sum to 180 o Such things can be known more certainly as they are universal and eternal

Scientific Knowledge n The demonstrations that constitute episteme Form a structure of linked deductions n Each link in the chain of deductions is such that the causes are more general than the subject and predicate being explained n

Intuitions Demonstrations are only as good as their premises n How do we come to know them? Choices are: n 1. Chain of premises and conclusions is endless Episteme is impossible 2. Chain is circular Knowledge has no foundation 3. First premises exist

Intuitions n First premises are known by induction from sense data Therefore we must possess a capacity of some sort [for getting knowledge without demonstration. ]. . . And this at least is an obvious characteristic of all animals, for they possess a congenital discriminative capacity which is called sense-perception.

Intuitions n First premises are known by induction from sense data But though sense-perception is innate in all animals, in some the sense-impression comes to persist, in others it does not. So animals in which this persistence does not come to be have either no knowledge at all outside the act of perceiving, or no knowledge of objects of which no impression persists; animals in which it does come into being have perception and can continue to retain the sense-impression in the soul.

Intuitions n First premises are known by induction from sense data And when such persistence is frequently repeated a further distinction at once arises between those which out of the persistence of such sense-impressions develop a power of systematizing them and those which do not. So out of sense-perception comes to be what we call memory, and out of frequently repeated memories of the same thing develops experience; for a number of memories constitute a single experience.

Intuitions n First premises are known by induction from sense data From experience again – i. e. from the universal now stabilized in its entirety within the soul, the one beside the many which is a single identity within them all – originate the skill of the craftsman and the knowledge of the man of science, skill in the sphere of coming to be and science in the sphere of being.

Intuitions n First premises are known by induction from sense data Thus it is clear that we must get to know the primary premises by induction (epagoge); for the method by which even sense-perception implants the universal is inductive.

Intuitions n First premises are known by induction from sense data Now of the thinking states by which we grasp truth, some are unfailingly true, others admit of error – opinion, for instance, and calculation, whereas scientific knowing and intuition (noûs) are always true: further, no other kind of thought except intuition is more accurate than scientific knowledge, whereas primary premises are more knowable than demonstrations, and all scientific knowledge is discursive.

Intuitions n First premises are known by induction from sense data From these considerations it follows that there will be no scientific knowledge of the primary premises, and since except intuition nothing can be truer than scientific knowledge, it will be intuition that apprehends the primary premises – a result which also follows from the fact that demonstration cannot be the originative source of demonstration, nor, consequently, scientific knowledge of scientific knowledge.

Investigations n Episteme is a structure of demonstrations Leading upwards from more general to more particular truths n Giving the causes of things n Based on undemonstrated conceptual truths n n We n discover the bases through intuition How do we discover the demonstrations?

Investigations n Collect facts of appearances (phenomena) It is owing to their wonder that men both now begin and at first began to philosophize; they wondered originally at the obvious difficulties, then advanced little by little and stated difficulties about the greater matters, e. g. about the phenomena of the moon and those of the sun and of the stars, and about the genesis of the universe. n The senses are generally reliable n It is their function to tell us about the world

Investigations n Consider reputable opinions (endoxa) As in other cases, we must set out the appearances and run through all the puzzles regarding them. In this way we must test the credible opinions about these sorts of experiences – ideally, all the credible opinions, but if not all, then most of them, those which are the most important.

Investigations n Apply dialectic (elenchus/Socratic Method/…) Dialectic is useful for philosophical sorts of sciences because when we are able to run through the puzzles on both sides of an issue we more readily perceive what is true and what is false.

Investigations n Apply dialectic (elenchus/Socratic Method/…) Furthermore, it is useful for uncovering what is primary among the commitments of a science; for it is impossible to say anything regarding the first principles of a science on the basis of the first principles proper to the very science under discussion, since among all the commitments of a science, the first principles are the primary ones.

Investigations n Apply dialectic (elenchus/Socratic Method/…) This comes rather, necessarily, from discussion of the credible beliefs (endoxa) belonging to the science. This is peculiar to dialectic, or is at least most proper to it. For since it is what cross-examines, dialectic contains the way to the first principles of all inquiries.