REVIEW LOGIC & REASONING Deductive Validity—formal A form such that true premises always true conclusions Informal test—imagine an argument in that form Core vocabulary: if..then.., and, or, not, all, some, none True premises & false conclusion Sound = df valid and all true premises “Conclusions of sound deductive arguments are true” Sound deduction from definition premises OTHER LOGICS Inductive—valid when good reasons for the conclusion Not a guarantee Analogy, induction on example(s), sampling, science Inference to the best explanation Practical syllogism: belief-desire to intention Needs an “ought” in premises INCONSISTENT TRIAD (DEDUCTIVE) If conclusion false then Either premise(s) false or invalid Formal test for validity Then key to Socratic rational doubt Doubt one of your premises Also key to science: hypothetical decuction Take current theory as hypotheses Measurements, mathematics Predict experimental outcome Outcome falsifiessome hypothesis wrong SOCRATES AND RELIGION APPLICATION Socrates no experimental method Needs explicit contradiction—harder Limits: reveals error not truth Plato cheats a lot No method to discover truth Problem of Evil even looser Needs formal statement unlike the usual Believer has many options Accept evil Best of all possible worlds: Free will Limited God Not creator THEODICY What God does not exist? is the alternative to no-evil? Why does it not prove that? Theodicy: possible solutions to the problem of evil Limited god (not perfect/omnipotent) Free will and necessary evil Necessary for greater good Human and divine “good” Or accept the conclusion Evil is an illusion Tutorials sign up Start next week 2 quizzes QUESTIONS? BACK TO SOCRATES: VIRTUE Use metaphysics model on ethics Fundamental reality of ‘virtue’, ‘justice’ Search for definitions using Socratic method one (conventions many) unchanging (vs. mores) knowable (definitions) rational (Socratic method) and Real (!) Why care about those peculiar facts? No man knowingly does evil WEAKNESS OF SOCRATIC METHOD No answers—Socrates the skeptic Dies ignorant Famous lament—and student response At least knows he doesn’t know 知之為知之不知為不知是知也 Deeper problem Many different consistent doctrines Contradiction not easy to prove Plato the playwright takes control SOCRATES AND PLATO STORY Death by legislature—wrong Plato’s hatred of democracy Better for policy and choice of leaders Not for judgment of guilt separate judiciary rule of law Socrates as figure in his dialogues Development of Socratic method Classic example in Thrasymachus dialogue PLATO'S SYNTHESIS: Parmenides: the real world and ethical ideal blend Real is rational; rational is real Focus on search for definitions Socrates origin and geometry The idea or concept of a thing Result is the meaning/value = being Really that being = meaning Meaning linked to value, purpose The concept is the thing’s “reality” ARE DEFINITIONS IMPORTANT? Not to knowing how to speak Vicious circle Real life and children learning Examples: true, cute, way, water Why such emphasis? Importance Socratic method and validity Problem to logical method of evil example Can’t test validity w/o form DEFINITIONS: CONCEPT REALITY Conform to rationalist presuppositions One – concrete instances are many Unchanging – remain; things change Knowable -- beliefs about objects Heraclitus and Parmenides Rational -- Socratic method Hence real Idealism Definitions (meanings:ideas) real Sensible “things" are not RULES FOR DEFINITIONS Implicit in Plato's Socrates No lists. What is common to all instances No vagueness. ‘Strong’? No circularity (or mere synonyms) Definition so usable in arguments No hearsay -- test by expert knowledge Real v. Nominal definitions Test by reason. Socratic method CONCLUSION: THE FORMS Forms correspond to definitions (meanings) Meaning “objects” Provide Metaphysics: what is real—objective meaning Like soul/mind--intellectual Logic: the thinkable objects Real definitions v. Nominal Epistemology: what is knowable unified answer to philo questions Not laws of thought but semantics Ethics: no man knowingly does evil Health of the soul Definitions of virtues Objects of striving -- teleological account of change DIFFICULTY: FAMOUS ANALOGIES Cave: sensible appearance v reality C.f. taking hallucinatory drugs Meditation or rational insight Analogy: shadow/object as object/form Equal difficulty in getting you to accept them When you "see" them, you will need no more convincing The character of the object determines your knowledge LINE ANALOGY: Links metaphysics and epistemology Knowability depends on nature of object (Parmenides) Rival view: true belief plus an account (the modern analysis) X knows that P =df. P is true X believes that P X has justification for believing that P THE SUN ANALOGY Rule for identification of forms Logic: there must be a form of forms It must be “more real” than the forms The form of the good: of all value Form of the truth/beauty/good MYSTICAL RESULT Absolute one/being No reason leading to see it It would blind us But necessarily there (or nothing exists) KEY POLITICAL DOCTRINES The Republic a political plan Justice of political structure like that of individual Same in everything Rule of the correct ruler— intellect THE PHILOSOPHER KING Anti-democratic and manipulative Education and classes Social ranks: intellectual, spirited, body-like END OF PLATO AND GREEK RATIONALISM Ancient Chinese idealism next!