Critical Thinking Lecture 1 What is Critical Reasoning?

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Critical ThinkingLecture 1What is Critical
Reasoning?

• By David Kelsey

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Course Objectives

• Thinking Rationally We will learn how to think
  correctly or rationally or logically.
• For someone to think rationally just means that
  she, from her set of beliefs, makes inferences
  that are justified given the laws of logic.

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The Laws of Logic

• The laws of logic dictate just which inferences
  we can make.
• They are rules for making good inferences.
• 2 examples
• Modus Ponens
• Modus Tollens
• Sentence letters

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Inferences

• An inference a statement that follows from one
  or more other statements.

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Statements

• A statement is a proposition.
• A proposition is the meaning of a sentence
• Just like words have meanings, sentences have
  meanings.

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Propositions

• The form of a proposition
• it is the case that.
• Propositions are true or false.

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Propositions Sentences

• A sentence does two different things it both
  expresses a proposition and asserts a
  proposition.
• The expressed proposition
• the literal meaning of the words of that sentence.

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Expressing a proposition

• For a sentence to express a proposition
• is for that sentence to toss the proposition up
  in the air, so to speak.
• It is to put the proposition up for usage.
• Knowing what proposition a sentence expresses

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The asserted Proposition

• Making use of a proposition
• Just how a sentence makes use of the proposition
  a sentence expresses determines its actual or
  intended meaning.
• The proposition asserted the actual or intended
  meaning of a sentence
• The actual or intended meaning of a sentence
• What the speaker or writer of the sentence means
  when she writes or says it.

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Miscommunication

• Miscommunication
• When the hearer doesnt take the sentence to
  assert what the speaker intends

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Sarcasm

• Other kinds of sentences
• Sarcasm
• The messy roomate
• She always takes out the trash.
• This sentence expresses
• But the sentence asserts
• Other occassions when meaning splits

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Arguments

• Arguments when one proposition is inferred from
  one or more other propositions
• Other definitions of an Argument

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Arguments

• Argument a position supported by reasons for its
  truth.
• To take a position
• An issue what is raised when one considers
  whether or not a proposition is true.

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Issues

• Issues
• we might go as far as to say that an issue just
  is a question.
• Intelligent life
• Safety belt law
• Mac vs. Pc

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Arguments Positions

• Arguments Positions so when we take a position
  on an issue and support it with reasons we have
  given an argument.
• Intelligent life
• Safety Belt law
• Mac vs. Pc

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Conclusions Premises

• Arguments
• The conclusion of an argument
• The premises of an argument
• Examples
• Socrates again
• April showers

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What an argument isnt

• What an argument isnt Let us be a bit clearer
  about what an argument is by stating what it
  isnt.
• Not a Fight
• Not Persuasion

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Persuasion

• Persuasion vs. Argument
• An argument offers support for some claim, its
  conclusion.
• Persuasion neednt offer any support for a point.
• Not Logic It merely attempts to get you to
  believe a point.
• Persuasion through rhetoric
• Rhetoric is a broad category of linguistic
  techniques people use when their primary
  objective is to influence beliefs and attitudes
  and behavior

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Arguments vs.Explanations

• Arguments vs. Explanations
• Explanation of X If one gives an explanation
  about some thing X, one gives some details about
  X with the hope of coming to better understand X.
• Example fixing a flat tire

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Recognizing Arguments

• Conclusion Indicators find the conclusion of an
  argument by looking for conclusion indicators.
• Examples of Conclusion Indicators therefore,
  hence, and others
• Premise Indicators find the premises of an
  argument by looking for premise indicators
• Examples of Premise Indicators because, since,
  and others

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An introduction to formalizing an argument

• Challenging an argument
• In challenging an argument you must first
  formalize it.
• Formalizing an argument
• Is the reconstruction of that argument in its
  most simplified form.

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Explicit Premises

• Explicit premises
• asserted by the words of the text.

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Implicit Premises

• Implicit or unstated premises entailed by the
  words of the text.
• Bloodhound example

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Factual claims

• Arguments and Claims
• Factual Claims
• Either true or false.
• Established methods
• Generally Established Criteria
• Settling Disagreement
• Example Water is H2O

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Non-factual claims

• Non-factual claims
• No established methods
• Cant settle Disagreement
• Some examples

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Value Claims

• Value claims non-factual claims that assert that
  some moral property is instantiated in some
  object or action or event.
• Properties and Moral Properties
• Never Ought from Is