Philosophy -- the very idea

1. Philosophy -- the very idea • The critical evaluation of and employment of standards of correct thought – especially when it comes to very foundational matters where the standards are not obvious and not clear • Etymological meaning: Love of wisdom • We are not sharing our opinions aimlessly • We are critically examining our opinions

2. Philosophy cont’d • Clarifying concepts and standards • Making distinctions • The role of puzzles • Connection with sciences

3. Popular opinion concerning philosophy • Pretentious nonsense • Special feelings • Studying famous madmen

4. Why does philosophy have a bad name? • Bad writing • Carried away by systems • Little practical relevance

5. Philosophy and other disciplines • Sciences/Math: Careful, methodical reasoning; abstract systems; seeking the truth; sensitivity to evidence • Humanities: Visiting and revisiting classic texts for insight, using all the resources of textual criticism (close attention to language, context, and so on)

6. Progress: a catalog of bad reasoning • We make mistakes all the time • Especially with tough, controversial issues: religion, politics, ethics, human nature • Reading and practicing philosophy gives us an opportunity to improve our reasoning skills, by catching others’ mistakes and catching our own mistakes

7. Mechanics of philosophy • Giving reasons • “The death penalty is unjust” • “God exists” • General principles • “It’s always wrong to kill a human being” • “If most people believe something, then it’s probably true”

8. Mechanics, cont’d • Testing general principles with thought- experiments • Counterexamples can disprove general principles • Revising general principles • Seeking wisdom vs. being contrary

9. Find counterexamples • All prime numbers are odd. • Anything that lives in the ocean is a fish. • It's always unreasonable to believe in something that cannot be seen. • Any behavior that's morally wrong ought to be illegal. • It's always wrong to break the law.

10. Find counterexamples, cont’d • You shouldn't criticize people for their beliefs. • All dogs have four legs. • Anyone wearing a mask of human skin, and wielding a blood-soaked chainsaw is dangerous.

11. Find the missing premise • “Same-sex marriage should not be allowed because it would undermine the traditional family.” • “Capitalist systems are unjust because they foster inequality.” • “Christianity deserves a special place in our national culture because our nation was founded on Christianity.” • “The traditional family serves to oppress women and, hence, it should be abandoned.”

12. Verbal disputes • The same term can be used with different meanings. • Often people think they’re having a real dispute, when really they’re having a merely verbal dispute – they’re just “talking past each other.” • Example: “liberty”, “racism” • Words are just labels; don’t fall in love with labels

13. Fallacies • = mistaken inferences (inference = transition from one statement to another) • If someone is Catholic, (s)he is pro-life. Joe is pro-life. Therefore, Joe is Catholic. • Joe might be a Jewish pro-lifer. • People with college degrees make more money than people without college degrees. So if you want to make more money, get a college degree.

14. Begging the question • Relying on disputed premises to establish a disputed conclusion. • The Bible says that God exists. If the Bible says it, then it must be true. Therefore, God exists. • Women has a right to control their own body in every single respect. Therefore, abortion should be legal.

15. Other fallacies • Circular reasoning • Appeal to authority • Ad hominem • Equivocation • “Some people say they want a free market. But why don’t they want to outlaw corporate exploitation that threatens our freedom?”

16. Jargon • Logic: the formal study of the connections between statements that can be true or false; logical: concerning logic • Not: intellectual, reasonable, sensible • Don’t say: “this book isn’t logical”, “he isn’t being very logical” • Do say: “I think he made a simple logical mistake” • No contradictions!

17. Argument: “a connected series of statements intended to establish a proposition” (Monty Python) • Not: a mean-spirited quarrel • Premises are the assumptions that go into an argument. Conclusions are the statements derived from the assumptions. • Arguments are often presented with numbered steps.

18. Valid arguments have a flawless formal structure – the conclusion follows from the premises with no ‘slack’. 1. Cows love Shakespeare 2. If cows love Shakespeare, then French toast is resentful 3. Therefore, French toast is resentful. • Valid arguments don’t have to be good arguments – just formally unproblematic.

19. Sound arguments are valid arguments with true premises. 1. All squares are quadrilaterals. 2. All quadrilaterals have four sides. 3. Therefore, all squares have four sides. • Each sound argument has a true conclusion. • After all, it has true premises, and the conclusion follows from the premises.

20. A really good (deductive) argument will be: • valid: the conclusion will follow from the premises • sound: not only is it valid, but it has true premises • interesting: its premises look plausible to those who would reject the conclusion • To really praise an argument, you can call it convincing, compelling, successful, powerful, or solid.

21. Propositions are statements that can be true or false. • “Close the door!” is not a proposition. • “Booo!” is not a proposition. • “What time is it?” is not a proposition. • “The cat is on the mat” is a proposition. • Don’t say, “this argument is false”, or “this inference is true”

22. Meaning is what synonymous linguistic expressions have in common. • The sentences Snow is white and Sníh je bílý and La neige est blanc have the same meaning (they express the same proposition). • The words dog and pes and chien have the same meaning. • Talk of the “meaning of life” (for example) is typically taken as figurative or secondary use of the term ‘meaning’

23. Necessary things would have existed, no matter how the world turned out. They have to exist. • Contingent things wouldn’t have existed, if the world had gone differently. They just happen to exist. • Possible things would have existed, if the world had gone differently. • Impossible things wouldn’t have existed, no matter how the world turned out.

24. Analytic truths are true just because of the meanings of the terms involved. • “All bachelors are unmarried” • “All ophthalmologists are doctors” • Synthetic truths are all the other truths. • “All cats have kidneys” • “Jerry Seinfeld is not dead”

25. A priori knowledge can be had without any experience of the world. • Mathematics, logic • A posteriori knowledge can be had on the basis of experience of the world. • Science

26. Two types of inference • Deduction: the logical derivation of conclusions from premises. (not Sherlock Holmes-style ‘brilliant speculations’) • All men are mortal. Socrates is a man. Therefore, Socrates is mortal. • Induction: tentatively endorsing a conclusion on the basis of many pieces of evidence. • This man is mortal. That man is mortal. That other man is mortal… Therefore, all men are mortal.

27. Reductio ad absurdum: A style of argument that aims to disprove a thesis by... 1. supposing, for the sake of argument, that the thesis is true, and then… 2. deducing contradictions (or absurdities) from the thesis. To show that there is no greatest integer, let’s suppose that there really were a greatest integer...

28. Different names for a philosophical view: position, thesis, doctrine, principle, theory • not: belief, feeling, opinion (these terms are commonly used to refer to the kinds of psychological states studied by psychologists and philosophers of mind) • Philosophers hold positions; also advocate, take, endorse, maintain

29. Branches of philosophy • Politics / Ethics / Aesthetics / Epistemology • Metaphysics • Phil. Mind • Phil. Language / Phil. Science / Phil. Math / Logic • Phil. Religion

30. Socrates Plato Aristotle St. Augustine St. Thomas Aquinas Descartes Hobbes Spinoza Locke Leibniz Berkeley Hume Rousseau Kant Hegel Marx Mill Wittgenstein Famous People

31. The Bleak Disenchanted ‘Scientific’ Worldview • All of existence is nothing more than a vast physical system of cause and effect. • Human thought and consciousness is nothing more than the mechanical functioning of our brain and nervous system. • Every human action is aimed at securing the selfish interests of that individual human. • Human action is directed by non-rational psychological forces like emotion and habit. • Every human action is completely determined by the physical system in place – there are no genuinely free choices. • There are no spirits, no souls, and no God.

32. The Comforting Common-Sense Worldview • There are many different aspects of reality – not just matter, but also personal minds. • Human thought and consciousness is a unique and very special part of reality. • Human action is at least sometimes aimed at helping others, or at doing what is right. • Human action can be directed by our capacity for reason. • Humans have a special capacity to make free choices, which are not determined by the outside physical system. • There is a God, and we are similar to God in having a mind, in having reason, and in having free will.