Transcript Reason - ToKMPI

By: Mitchell Heidenreich and Ryne Yamada
Reason
 “You are not thinking, you are just being logical.” - Frisch
 “Logic is the beginning of wisdom but not the end.” 
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Leonard Nimoy
He that will not reason is a bigot. He that cannot reason is a
fool. He that dares not reason is a slave. - Branch Rickey
“A madman has lost everything but his reason.” - G.K.
Chesterton
“The head is always fooled by the heart.” - Aaron Ben-Ze'ev
“I think therefore I am.” - René Descartes
Deductive Reasoning
 Moving from general to particular
 Example: All dongs are mammals, Dario is a dog,
therefore Dario is a mammal.
 We go from all dogs to Dario. These are called
syllogisms
Examples
All oranges are fruits
All fruits grow on trees
Therefore, all oranges grow on trees
All bachelors are single
Johnny is single,
Hence, Johnny is a bachelor
Syllogisms
 A Syllogism is a form of argument that contains a
major premise, a minor premise and a conclusion.
 They have toe premises and one conclusion
 They have three terms, each which occurs twice (dog,
mammals, Dario)
 They have quantifiers such as ‘all’, ‘some’, or ‘no’
Truth vs. Validity
 Statements can be true or false
 Arguments are valid or invalid
 Arguments can be valid and still not true
 All flowers are pretty. Ms. Yellow is pretty. Therefore
Ms. Yellow is a flower.
 Pure logic is only concerned with the structure of an
argument
Create Your Own Valid Syllogiam
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Two true premises, and a true conclusion
One true premise, one false premise, and a true
conclusion
One true premise, one false premise and a false
conclusion
Two false premises and a true conclusion
Two false premises and a false conclusion
Knowledge Issues
Reasoning
 Good logic is valid because the premises and
conclusion are logical but not always true
 Avoid fallacies or failures in logic
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What is the missing premise of these syllogisms?
Brian goes to MIT, so he is smart.
John is smart so he can’t play sports
Mr. T is a politician, so he is probably lying
Drugs should be legal because they only harm the user
Inductive Reasoning
 Moving from the particular to general
 Metal A expands when heated, as does metal B and C.
Therefore, all metals expand when heated.
 We went from Metals A, B, C to all metals
 Use Inductive reasoning everyday
 My neighbor’s dog didn’t bite me in the past, so he
wont bite me today either
 My chair supported my weight in the past, so it will
hold my weight today
Rationalism
 Any view appealing to reason as a source of knowledge
or justification.
 Modern rationalism adds a third 'system of thinking'
 Rationalism makes equal reference to all three systems
of thinking.
 An example of abstract thinking is Pythagoras' concept
of 'pure' geometric forms: perfect triangles, squares,
circles.
 Another example is imaginary numbers, in
mathematics.
The 10 Deadly Reasoning Fallacies
 Ad ignorantiam - the fallacy of inferring a statement
from the absence of evidence or lack of proof of its
opposite.
 Hasty generalization - drawing conclusions based on
insufficient or unrepresentative evidence
 Post hoc ergo propter hoc - Confusing a correlation
with a causal connection.
 Ad hominem - attacking/supporting the person rather
than argument.
 Circular reasoning - assuming the truth of what you
are supposed to be proving.
The 10 Deadly Reasoning Fallacies
 Special pleading - using double standards to excuse an
individual or group
 Equivocation - using language ambiguously
 False analogy - assuming that because two things are
alike in some respects they are alike in other respects.
 False dilemma - assuming that only two black and
white alternatives exist
 Loaded question - a question that is biased because it
contains a built-in assumption
Ad Ignorantiam
Irrationality
 With rationality resembling knowledge meanwhile
irrationality would refer to true opinion.
Doubting reasoning
 Logic and reason have no explanation for something
 Quantum Events
Lateral Thinking
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Reasoning that actively resists the logic errors
One way to express this is to “Think Outside the Box.”
Think of a logical reason for these situations:
A man walks into a bar, asks for a glass of water. The
barman pulls out a gun on him. The man thanks him
and walks out.
 A man lies dead in a field by an unopened package.
There is no one around. How did he die?
 In the middle of the ocean is a yacht. Several corpses
are floating in the water nearby