Week 2:

Logic and Epistemology

TOK, p. 115-132Selected Readings

TOK Chs. 7-8, p. 94-132

Team 1: 94-100Team 2: 101-106Team 3: 107-113Team 4: 114-120Team 5: 121-127Team 6: 128-132

Where we are Going?

• Blog 1: Gun Control Argue Out Teams (10 Minutes)

• Notes: Ch.1-3 (18 min., 3 min. each)

• Finish Week 1: – What is a Knower? – Intro to Ways of Knowing

• Start Week 2: – Activity 3: Witch Trial– Laws of Logic– Formal and Informal– Fallacies– Blog 2: Fallacies

Loftus and Palmer (1974)

• Elizabeth Loftus investigated the interaction between language, memory and eyewitness testimony.

• Conclusions:– The way a question is

worded often leads to a new reconstruction of a memory

– Eyewitness testimony and estimations are often a dependent variable.

– What other factors contribute to memory dependancy?

Memory• Memory and testimony are the

cognitive foundation of the "knower"– Neurologically, memories are

chemical reactions resulting from synapse activation within the brain.

– Rationally, memories are the calculator and "rulebook" that allows for proper and logical thinking.

– Emprically, memories are the record of our senses reconstructed through will or by outside stimulai

– Pragmatically, memories are the priorities of the world in which p;ersonal meaning is constructed.

• Do we have memories of the way things are, or is there always personal bias? Do our senses create accurate pictures of reality?

The Ways of Knowing

• Reason– Analytic and synthetic– a priori or a posteriori– constructs of logic that define a thing

or to define basic laws using symbolacrae

• Sense Perception– Correspondance testing between

memory and seeing, etc.– Basis for scientific philosophy.– Often subjective and vulnerable to bias.

see aesthetic philosophy.

• Intuition/imagination (?)– Memories reconstructed often with

disregard for the backward looking sense perception and/or rationality to project to future events, develop innovative hypothesis, or to be a great artist.

The Ways of Knowing

• Language– The symbols that connect our

thoughts to others– Intrinsically indirect and

requires assumptions about the world (such as the existence of other minds).

– Often can present challenges to synergy of information

• Emotion– The personal reaction and

cultural parameters of expression connecting to others by thou

Tests of “Truthiness”

• Correspondence– Statements are true so much as the

relate to actual, observable data from the world.• “The snow is white”

• Coherence– Statements are true so much as they

are logically consistent with previous beliefs about the world.• “there are no pink elephants in Lake

Elsinore because I know elephants are gray, live in africa…etc.”

• Pragmatic– A statement is true if +it allows you to

interact effectively and efficeintly with the cosmos.• “My belief that inanimate objects do not

spontaneously get up and move about is true because it makes my world more predictable and thus easier to live in. It “works”

Testimony or Knowledge by Authority

• Information about the world often comes through degrees of testimony– Data is received, passed,

written, consolidated, taught, and recited.

• How might the “authority fallacy” be different than “knowledge by authority?”

• List 10 things you know by authority

• List 10 things you know by personal testimony.

Knowledge Prism

• Knowledge is reliant upon various presuppositions:– Rationality, laws of logic, and

language can be used consistently and with meaning

– Statements and observations can be investigated against counter-factuals to correspond some semblance of “external world” and “the way things really are”

– An identity and mind to process, articulate, and construct a worldview based on observation and truth statements.

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Rationality

Knower

Rational and Empirical

• What is the difference between the following phrases?:– “2+2=4”– “This cat is orange.”– “I was probed by an alien last

night.”

• Rationality: intuited propositions deduced towards knowledge. – A priori knowledge

• Empiricism: Knowledge and concepts needed for knowledge come from our senses and perception.– A posteriori knowledge

Plato: “Justified True Belief”

• Knowledge, according to Plato, has three parameters:– Justified: Is a truth claim in

the realm of falsifiability?– True: is there enough

evidence or reasonable argument for its probable correctness?

– Belief: do I internalize and assume the claim into my worldview and understanding

Acquaintance vs. Description

• “If you can’t say it, you don’t know it” – Hans Reichenbach (German

philosopher of science, 1891-1953)

• “I know more than I can say.”– Michael Polanyi (Hungarian

philosopher of science, 1891-1976)

Imagination• “I am enough of an artist to draw freely

upon my imagination. Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.” 

• “Everything you can imagine is real”

• “We are what we pretend to be, so we must be careful about what we pretend to be.”

• Can Imagination be a source of knowledge? What would its limits be? Can you know something that is only feasible in your mind?

Week 2:

Logic and Epistemology

TOK, p. 94-132Selected Readings

TOK Chs. 7-8, p. 94-132

Team 1: 94-100Team 2: 101-106Team 3: 107-113Team 4: 114-120Team 5: 121-127Team 6: 128-132

Activity 3: The Illogical Game

• Watch the following clip from Monty Python’s Quest for the Holy Grail

• Identify 5 statements that “don’t add up” based on your prior knowledge and common sense

• In teams of four, see if you can identify the formal and informal fallacies behind your statements. List them out.– If you don’t know the names, try

and describe/explain why they are illogical.

Break down of the Argument

1. All witches are things that can burn. 2. All things that can burn are made of wood. 3. Therefore, all witches are made of wood. (from 1 & 2)

4. All things that are made of wood are things that can float. 5. All things that weigh as much as a duck are things that can float. 6. So all things that weigh as much as a duck are things that are made of wood. (from 4 & 5) 7. Therefore, all witches are things that weigh as much as a duck. (from 3 & 6) 8. This thing is a thing that weighs as much as a duck. 9. Therefore, this thing is a witch. (from 7 & 8)

Laws of Logic

• 1. Law of identity.– Everything is what it

is. A is A or A is Identical with A.

• 2. law of Contradiction. – A cannot be A and not

A at the same time.

• 3. Law of Exculded Midddle. – A is either a or not A

Formal Logic

• Syllogism– Two statements that create

conditions towards and absolute conclusion statement.

• Distribution– A line in logic that is

properly moving from specific to general (i.e. all cats are mammals) based on language.

• Modus Ponus– Form of logical reasoning

that forms the basis of all formal logic

Deductive Reasoning

• Taking general statements of truth about the world and reasoning towards a specific conclusion.

• Formal logical constructs like the modus ponens are deductive

Inductive Reasoning

• Inductive reasoning is perhaps the opposite of deduction

• One takes specific statements and arrives at a general conclusion/principle

• Which is more scientific?

Formal Fallacies

• Affirmative conclusion from a negative premise (illicit negative) – when a categorical syllogism has a positive conclusion, but at least one negative premise.

• Fallacy of exclusive premises – a categorical syllogism that is invalid because both of its premises are negative.

• Fallacy of four terms (quaternio terminorum) – a categorical syllogism that has four terms.

Formal Fallacies

• Illicit major – a categorical syllogism that is invalid because its major term is not distributed in the major premise but distributed in the conclusion.

• Illicit minor – a categorical syllogism that is invalid because its minor term is not distributed in the minor premise but distributed in the conclusion.

Formal Fallacies

• Negative conclusion from affirmative premises (illicit affirmative) – when a categorical syllogism has a negative conclusion but affirmative premises.

• Fallacy of the undistributed middle – the middle term in a categorical syllogism is not distributed.

Quick Application

1. If it's raining, I'll meet you at the movie theater.

2. It's raining.3. Therefore, I'll

meet you at the movie theater.

• Modus Ponens

Quick Application

• If the cake is made with sugar, then the cake is sweet.The cake is not sweet.

• Therefore, the cake is not made with sugar.

• Modus Tollens

Quick Application

• Either the Sun orbits the Earth, or the Earth orbits the Sun.The Sun does not orbit the Earth.Therefore, the Earth orbits the Sun.

• Disjunctive Syllogism

Quick Application

• Everyone who drives at 80 MPH is speeding

• All who speed break the law.

• Therefore, everyone who drives at 80 MPH breaks the Law

• Reasoning by Transivity

P->QQ->R______Therefore: P->R

Quick Application

• No fish are dogs, and no dogs can fly, therefore all fish can fly.

• We don't read that trash. People who read that trash don't appreciate real literature. Therefore, we appreciate real literature.

• Affirmative conclusion

• If A ⊄ B and B ⊄ C then A ⊂ C.

Quick Application

• No mammals are fish.

• Some fish are not whales.

• Therefore, some whales are not mammals.

• Fallacy of exclusive premies

• No X are Y.• Some Y are not Z.• Therefore, some Z

are not X.

Quick Application

• All fish have fins.• All goldfish are fish.• All humans have

fins.

• Fallacy of four terms

Quick Application

• All dogs are animals. 

• No cats are dogs. • Therefore, no cats

are animals.

• Illicit major

Quick Application

• All cats are felines.• All cats are

mammals.• Therefore, all

mammals are felines.

• Illicit minor• All A are B.• All A are C.• Therefore, all C are

B.

Quick Application

• All cats are animals.

• Some pets are cats.

• Therefore, some pets are not animals.

• Negative conclusion from affirmative premises (illicit affirmative)

• if A is a subset of B, and B is a subset of C, then A is not a subset of C.

Quick Application

• Money is green • Trees are green, • money grows on

trees.

• Fallacy of the undistributed middle

• All A's are C's. All B's are C's.

• All A’s are B’s

Informal LogicAd HominemA personal attack: that is, an argument based on the perceived failings of an adversary rather than on the merits of the case.

Ad MisericordiamAn argument that involves an irrelevant or highly exaggerated appeal to pity or sympathy.

BandwagonAn argument based on the assumption that the opinion of the majority is always valid: everyone believes it, so you should too.

Begging the QuestionA fallacy in which the premise of an argument presupposes the truth of its conclusion; in other words, the argument takes for granted what it's supposed to prove. Also known as a circular argument.

Informal LogicDicto SimpliciterAn argument in which a general rule is treated as universally true regardless of the circumstances: a sweeping generalization.

False DilemmaA fallacy of oversimplification: an argument in which only two alternatives are provided when in fact additional options are available. Sometimes called the either-or fallacy.

Name CallingA fallacy that relies on emotionally loaded terms to influence an audience.

Non SequiturAn argument in which a conclusion does not follow logically from what preceded it.

Informal FallaciesPost HocA fallacy in which one event is said to be the cause of a later event simply because it occurred earlier.

Red HerringAn observation that draws attention away from the central issue in an argument or discussion.

Stacking the DeckA fallacy in which any evidence that supports an opposing argument is simply rejected, omitted, or ignored.

Straw ManA fallacy in which an opponent's argument is overstated or misrepresented in order to be more easily attacked or refuted.

Activity 4:

• In teams of 4 watch the following videos on your iPad by going to tctok.us

• Identify the primary fallacy being used.

• Explain why it is being used. Why is it effective?

• Discuss how a topic could have been approached should the fallacy be corrected (avoid bias)

Blog 3: Logical Argument

• Create a logical proposition with a formal or informal fallacy.

• Respond to another student’s proposition with the correct identification. Offer a correction.

Blog 3: Logical Argument

• Decide on a position that you care deeply about.

• Find someone online (blogs, youtube, facebook, etc.) who you agree with on this position, but can see a logical fallacy in their presentation.

• Write your position, their quote, and an analysis of the fallacy in one paragraph.

Thinker Portrait: Rene Descartes