Review Chapter 8 Deductive Reasoning

Deductive Logic Classical: by putting in proper form we will force conclusion – Standard Form – Putting things in classes Modern: by showing flow of argument we will force conclusion – Proofs – Mini-valid arguments

Classical Logic, Syllogism The rule of three: ties argument together All arguments must only have three lines (2 premises and 1 conclusion) and three terms All lines have subject-predicate relationship Putting the subject term into a certain class The Inference- how terms are arranged – Major term- pred. in conclusion + one premise – Minor term- subject in conclusion + one premise – Middle term- term in both premises, not in concl.

Mood + Figure = Form

Mood Each line can only be 1 of 4 mood types – A: All S are P – E: No S are P – I: Some S are P – O: Some S are not P Full argument has a 3 letter mood (AIE) 64 possible mood types

Figure Figure is where the middle term is placed Mood + Figure = Form 64 X 4 = 256 possible forms

Form Valid forms – 15/256 are valid standard form arguments Set up in a manner that: Forces you to accept the conclusion if both the premises are true Sound argument is set up in a valid way and has ALL true statement. In the end it is the way we set up our argument that allow us to check if it is valid and sound.

Modern Logic Doesn’t force us to set up arguments in any way or format – Do need one statement as a conclusion – As many premises as you want Proven deductive rules (mini-arguments) can show the flow of logic (reason)– Inference These are called proofs– much like geometry 9 elementary rules/ you need to know 4

Four Rules Modus Ponens (M.P.) If P then Q P Therefore Q Modus Tollens (M.T.) If P then Q Not Q Therefore not P Hypothetical Syllogism (H.S.) If P then Q If Q then R Therefore if P then R Disjunctive Syllogism (D.S.) P or Q Not P Therefore Q

1. I  (C v K) 2. I 3. ~C 4. K  (~S E) 5. M  S / Therefore ~M 6. C v K (1)(2) MP 7. K (6)(3) DS 8. ~S E (4)(7) MP 9. ~S (8) Simp. 10. ~M (5)(9) MT

Language and Communication Chapter 3

Arguments- Logic Argument are only as good as our expression of them – Way you communicate – Language you use – Not one way to express them Two way street Logic can also…. – Help us organize our arguments better – Help us decipher good and bad arguments Communication is getting your ideas across in a clear & logical manner (choice you make)

Language, meaning & communicating Recognize which definition we are discussing – Definition can be subjective – We make the dictionary (we agree on words) Clear up “messy” language or definitions – Not universal – Words with multiple meanings and punctuation Word definitions are built, not given to us & Words change meaning with time & New words come into common vocabulary, old words go away

Language Symbols that we place meaning on (spelling and grammar) Need to agree on definition and the value of words used 4 types of languages – Informative Making a statement (true or false) This is where logic is concerned – Expressive Expresses your feelings, use emotional words (Poetry) – Directive Influence people’s actions (Get up!) – Ceremonial We say these things to be polite or accepted Greeting: ‘hello’, ‘good morning’, ‘how are you’ Some statement cross over two or more types

Word Meanings Denotative meaning (objective) – Tells us what characteristics and features that we associated with that given word – Dog = tail, four legs, barks, big ears (?) Connotative meaning (subjective) – Descriptive definition – Tells us personal experiences with that object – Dog = licks face, loyal, protects me Stereotype meaning (necessary) – Loosely defines individuals as a group – Obviously we want to limit, not abuse – Individual things fit into MANY groups

Own Words and Communication Evaluating definitions Definition has to fit – Not too broad, not too narrow Does it include all the denotative attributes to the meaning – Does the abject have all the features. Dog = 4 legs, fur, barks – Is it necessary to add features, change meaning (ex: computers) Not circular – Do not use term or word to define itself Justice: when someone receives justice Definition is clear – Make sure the words being used to define have clear definitions themselves. – Net: anything reticulated lines at equal distance with intersections of small narrow space between the intersections Avoid emotional language, rhetoric and assumptions

Four styles of communication Aggressive: Communicate own needs by controlling other people with manipulation Passive: Communicate to avoid confrontation and put others needs ahead of their own Passive-Aggressive: Communicate to avoid direct confrontation but use manipulation to get their needs fulfilled. Assertive: Communicate own needs and strive for mutually agreed upon solution. This takes good critical thinking skills

Types of definitions Meanings we place on words

Stipulative Definitions A new definition or a change in an old definition – Laws and technology deal with this all the time “Morally straight” – Boy Scouts, 2000 Public Domain and Internet Copyright and Internet Facebook and lines of privacy – These become defined by the court and ultimately the Supreme Court – Most the time they start off as slang Mankini Friending Beer goggles These become official when entered into dictionary– common

Lexical Definitions Is official dictionary definition Is it used by enough people to be accepted as a commonly held definition Purpose – Increase our vocabulary to explain new things – Clear ambiguity and meaning These definitions are always changing – Marriage (man and woman?) – Lubitorium (gas station) – Cold (weather, people, gambling, sports)

Precising Definition Used to clear up words and phrases We customize dictionary definitions to suit our needs – Term paper (depends on class/teacher) – Learning disability (depends on expectations) Occurs because dictionary definition is too vague Definitions are made by a group or people who use the term in their field of study or employment – International Astronomical Union: Pluto planet/dwarf planet (2006)? – Each company defines: Full time employees? – Each court defines: Justice to the people?

Persuasive Definitions Used to influence others about your point of view – Taxation – “governmental robbery” – Genetic engineering – “playing god” – Politicians- “fat cats” More important to convey individual EMOTION and not valued INFORMATION Biased in nature– “Here is what I think!” The truth is usually not important it is getting people to side with your beliefs. – Offer little or no evidence – Don’t look for other options

Communication = We discuss matters that are not one sided. You don’t have to agree, but you need to listen and respond to be able to communicate– It’s a choice Historically the top three skills 1.Communication 2.Teamwork 3.Commercial Awareness

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