WOK: REASON
What is the difference between reason and logic? How reliable is inductive reasoning?
Are we predictably irrational?
Are we predictably irrational?
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Reason allows us to go beyond the immediate experience of our senses. It is closely linked to logic— the deducing of valid conclusions from given starting points or premises. Human reasoning can also be inferential in nature, allowing conclusions to be drawn that cannot be strictly deduced from their premises. It then becomes an interesting question of whether standards of rationality and norms of reasoning are grounded in culture. Areas of knowledge might set their own requirements for the types of reasoning that are accepted.
Inductive reasoning is the process of supporting general statements by a series of particular ones—the reverse of deductive reasoning which tends to proceed from the general to the particular. Inductive reasoning is by its nature inferential. Statements involving the word “all” are often not strictly provable given the difficulties in making observations of an infinite set of particulars. This is of importance in the natural sciences but also in human sciences such as psychology and economics. Theory of Knowledge guide |
DA 1: |
Think and share how and why does/can culture affect our reasoning?
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REASONING BY LEVELS
LEVEL 1: THE ELEMENTS OF AN ARGUMENT
ARGUMENT:A group of statements with ONE OR MORE premises and ONLY ONE conclusion.
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PREMISE:A statement that is the base of the argument and is followed by a conclusion.
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STATEMENT: |
CONCLUSION: |
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A sentence that is either true or false.
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A statement derived from the premises.
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All students in Escuela Bella Vista are awesome. Ana is a student is Escuela Bella Vista. Ana is awesome.
P1 P2 C
All fruits are healthy. Melon is a fruit, then eating Melon is healthy for you.
LEVEL 2: DEDUCTIVE VS INDUCTIVE REASONING
DEDUCTIVE REASONING
general to specific
logic |
INDUCTIVE REASONING
specific to general
generalizations, observations |
LOOK AT THE FOLLOWING EXAMPLES
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The Avila sisters are 5, 8, 10, 15 years old.
Andreina is 5, Angela is 10 and Isabella is 15. Then, Ana is 8 years old. |
It has rained in Maracaibo every September for the last 5 years.
Therefore, it will rain in Maracaibo this upcoming September. |
ACTIVITY 1: READ THE EXAMPLE GIVEN AND DETERMINE WHETHER IS A DEDUCTIVE OR INDUCTIVE ARGUMENT. BE READY TO EXPLAIN WHY.
ACTIVITY 2: WRITE TWO EXAMPLES OF EACH KIND OF ARGUMENT (4 TOTAL)
DA 2: |
Write in your own words the definition of deductive and inductive reasoning and explain the difference between the two (provide examples). |
WHO IS THIS GUY AND WHAT DID HE DO?
LEVEL 3: LOGIC AND SYLLOGISM
Syllogistic logic studies arguments based on words like ALL, NO, NOT, SOME.
A syllogistic argument is called a WFF:
well-formed formula
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1. All flowers smell good (Universal - affirmative)
2. No fish can fly (Universal - negative) 3. Some vegetables taste good 4. Luis does not believe in religion (Particular - negative) 5. All humans are mortal. 6. Isabella's name does not start with an A. 7. Diego read the book. 8. No atheists believe in God. 9. The bag on your desk is purple. |
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SYLLOGISTIC LANGUAGE
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CAPITAL LETTERS for GENERAL CATEGORIES
All flowers (F)
No fish (F) All humans (H) No atheists (A) |
small letters FOR particular categories
Luis (l)
Isabella (i) Diego (d) the bag on your desk (b) |
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presidents
Obama dogs schools EBV this book |
oceans
the Pacific Ocean Spain Mario authors rose |
Maracaibo
months hospitals TOK letters words |
8 Common WFFs
All WFFs use the verb is. The verbs in the statement can be transformed into is or are for better understanding.
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All flowers smell good
ALL F is G No fish can fly No F is F |
Some vegetables taste good
Some V is G Luis does not believe in religion l is not R |
Hint: When a WFF begins with a word you use capital letters, when a WFF begins with a letter you use small letters.
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All humans are mortal.
Diego read the book. The bag on your desk is purple. |
Isabella's name does not start with an A.
No atheists believe in God. Not all sentences are true. |
ACTIVITY: WRITE AN EXAMPLE OF A WFF FOR EACH CATEGORY WITH ITS TRANSLATION TO SYLLOGISTIC LANGUAGE.
WARNING
After reviewing the last activity, you need to look at this note:
LEVEL 4: SYLLOGISMS AND VALIDITY
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A syllogism is a logical argument based on deductive reasoning formed by WFFs. It contains premises that derive into a conclusion.
All chocolates are made from cocoa beans. Toronto is a kind of chocolate. Therefore, Toronto is made from cocoa beans. All C is B
s is C ∴ s is B |
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How Do We Know If an Argument Is Valid?
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Major Premise
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In this case, the major term of the major premise forms the predicate of the conclusion. The minor term of the minor premise forms the subject.
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ACTIVITY 1: Create an argument - trade it with a partner - depict it on the whiteboard using the Venn diagram - check its validity
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ACTVITY
In pairs, research about one logical fallacy and be ready to present it to the class (20 minutes)
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HERE ARE SOME RESOURCES FOR YOU
Identify the following logical fallacies:
1. Attacking an argument based on the person's religious beliefs.
2. Claiming that a restaurant is great because a lot of people visit it.
3. Claiming that video games are bad for kids because they become more violent and eventually criminals.
4. Claiming that something is true because my teacher says it is.
5. Claiming that eating meat is bad because it makes you sad to think of all those poor cows.
6. Stating that you either follow a rule or you don't agree with it.
7. A person says that she thinks her friends should not be so rude to the new girl. Another person says that she cannot believe that he/she is choosing to be better friends with the new girl than the girls who have always known him/her.
2. Claiming that a restaurant is great because a lot of people visit it.
3. Claiming that video games are bad for kids because they become more violent and eventually criminals.
4. Claiming that something is true because my teacher says it is.
5. Claiming that eating meat is bad because it makes you sad to think of all those poor cows.
6. Stating that you either follow a rule or you don't agree with it.
7. A person says that she thinks her friends should not be so rude to the new girl. Another person says that she cannot believe that he/she is choosing to be better friends with the new girl than the girls who have always known him/her.