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Review
 Start of Western philosophy = metaphysics
 Explanatory science—Thales “all is water”
 Explanation by
 a) many explained by one
 b) change explained by something permanent
 Knowing is knowing the permanent, one . . .
 Assumptions shared by Indian thought
 Many other candidates proposed for the “one”
Heraclitus
 Same assumption—nothing is real
 Everything is changing
 Famous river example
 Grammatical root (countable nouns v mass nouns)
 One permanent while the other changes
 Everything is “becoming” – each thing is a
contradictory mix of being and not-being
 Only the law (logos) of change is unchanging
 The only thing knowable (rest is mere belief)
Parmenides: Being
 Exact opposite: nothing changes
 Primacy of reason over experience
 Experience an illusion/dream
 What is is; what is not is not
 Truths of reason (tautologies/analytic truths)
 Proof: Subject Term must refer
 Or the sentence is necessarily false (?)
 Santa Claus is married
 We cannot speak of “what is not” without
contradiction
Questions
Tutorials after CNY
Syllabus Correction
Quiz on argument.
Second Element
 Focus on concept of “being” (is)
 ‘Being’ tied to the Indo-European verb--to be
(copula)
 Two uses in Indo-European languages
 Predicative and existential
 Predicative: make a sentence or assertion
 Links adjective/noun to a subject
 Not needed in Chinese 她很漂亮
 To describe a thing is to say what "is" of it
 What its being or existence includes.
Existential
 “X is” = X exists = there is (有) X
 Blending the two uses leads to the view
that all change is impossible—why(?)
 To describe a change entails that it is what it
was not before
 This is to change “is not” to “is”
 Parmenides construes change as non-being
becomes being
 That is impossible
 Hence change is impossible
Classical Chinese Case
 Literary Chinese has no “is” copula
 “Exists” expressed with 有無
 Also no required subject term
 Doesn’t have a puzzle about how being
can change
 This “Perennial” problem turns out to be a
problem of only one philosophical culture
 A problem rooted in the language or
grammar
Guo Xiang: Like Parmenides
 無 cannot become 有 and 有 cannot
become 無
 Although it changes constantly, it never
ceases to exist
 So accepts that reality is in constant change—
no problem
 Can deny movement from non-being to being
without denying all change 化
Other Western examples: Zeno
 Arrow paradox: infinite number of points
 Same conclusion. No change
 Additions to Rationalist Dichotomies
 Reason v. experience
 Real v. apparent
Classical Greek Rationalism
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One
Permanent
Knowable
Rational
Reality
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Many
Changing
Believed
Experienced
Mere-appearance
Framework of appearance v. reality
Other sources of Rationalism:
 Pythagoras: Geometry and Pythagorean
theorem
 Religion of worship of math objects: points,
lines etc
 Euclid: (After Plato) axiom-theorem
structure. How to think
 A powerful conception of the organization of
knowledge
 And about the world—real shape of things
Socrates
 Dissatisfaction with the naturalists
 Powerful techniques but unimportant
questions
 The examined life
 focusing on the Indo-European concept of
"soul"
 Seat of reason, consciousness, and intellect
 Morality and right
 Soul's health the most important thing
Brought method to attention.
 Method is proof; target is definitions
 A definition of 'justice' or other virtues
 Understand what it is
 Conclusions conform to rationalist
dichotomies
 Socratic Method
 Doubt—but much more
 Rationally motivated doubt
Logic
 Socratic method requires a look
 Logic as disciplined discourse
 'Argument': proof v quarrel sense
 Proof consists of sentences
 Premises and conclusion
 Conversational implication
 Conclusion “follows from” the premises
 Needs explanation
Good and bad arguments proofs)
 Valid: has a form such that if the
premises were true, the conclusion
would be true also
 Formal or symbolic representation a
consequence
 Venn diagram technique
 Classic example: all C are B, all B are A, all
C are A
Validity
 A matter of form
 Like grammar: need form to
express a thought
 Argument form such that if
premises (in that form) were true,
the conclusion (in that form) would
also be true
Called Formal Or Symbolic
Logic
 Modus Ponens: if P then Q; P; hence Q
 Modus Tolens: if P then Q; not Q; hence
not P
 Disjunctive syllogism: either P or Q; not P;
hence Q
 Famous invalid form
 Affirming the consequent: if P then Q; Q;
hence P
Study Of Validity
 Symbolic/formal logic
 If … then. .., All, some, none,
either. . . or . . .
 Study formal structures
How to Prove Invalidity
 Use the same form
 With plainly true premises
 And a false conclusion
 Can not be a valid form
 Distinguish from argument by analogy
 Form of induction on a similarity
 How do I know you have minds?
Soundness
 Definition
 Valid argument
 True premises (all)
 Conclusion of two definitions
 Sound arguments have true conclusions
 What if conclusion of valid form is false
 Opposite of “all” is “one or some”
 At least one premise is false
Other Logics
 Deductive v inductive
 Guarantee by form v good reason for
conclusion
 Could still be wrong
 Weakest to strongest
 Analogy (weak form) one likeness
 Classical induction: next one might change
 Sampling, polling and statistics (with rigor)
 Science (strong form) explain later
 Inference to the best explanation
Moral Or Practical Reasoning
 Uses the same model: called the practical
syllogism
 Belief-desire explanation of action in western
thought
 To get a value (ought) conclusion, you
need a value premise
 You can't get an "ought" from an "is"
 Abortion argument example
Crucial Move:
 If conclusion false, then either invalid or
premise false
 Key to scientific induction (v. Classical
induction)
 Laws and experimental setup predict a result
 If prediction is false, one of the premises must
be false
 Usually the setup, but after repeated checking calls
one of the laws into question
Socratic Contradiction
 Socratic method no experiment
 Use argument to derive a contradiction
 Must change a premise. Not necessarily the
definition
 Limits of Socratic (scientific) method: only
exposes error not truth
 Trial and error, creativity, insight, genius for
premises
Example: The Problem of Evil
 God is omnipotent, omniscient and all
good creator of everything
 Hence, there is no evil
 Formal statement: ABCD. All good
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"All things there are”
"things God made"
"things God wanted"
"good things“
Theodicity
 What is the alternative to no-evil?
 God does not exist? Why does it not prove
that?
 Theodicity: possible solutions to the problem
of evil
 Limited god
 Free will and necessary evil
 Human and divine “good”
Back to Socrates: Virtue
 Applies metaphysical analysis to ethics,
truths are moral facts.
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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 cheats!
Socrates and Plato Story
 Death by legislature—bill of attainder
 Plato’s hatred of democracy
 Better for policy and choice of leaders
 Not for judgment of guilt
 Takes Socrates as a figure in dialogues
 Source of our account of Socratic method
 Classic example in Thrasymachus dialogue
Plato's Synthesis:
 Parmenides: the real world and ethical
ideal blend
 Focus on search for definitions
 Socrates origin or geometry
 Result is that meaning/value = being
 Really that being = meaning/value
Definitions:
 Conform to rationalist presuppositions
 One -- instances are many
 Unchanging -- remain while that kind of thing
 Knowable -- beliefs about objects (Heraclitus
and Parmenides)
 Rational -- Socratic method
 Hence real
 Idealism. Definitions (meanings:ideas) are real
 "Things" are not
Rules for Definitions
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Implicit in Plato's dialogues with 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
 Intellectual forms correspond to definitions
(meanings)
 Forms provide a unified answer to questions in all
fields of philosophy
 Metaphysics: what is real. Real definitions v. Nominal
 Epistemology: what is knowable. Like soul/mind-intellectual
 Logic: the thinkable objects (not laws of thought but
semantics)
 Ethics: no man knowingly does evil. Health of the soul
 Objects of striving -- teleological account of change