Critical Thinking and Logical Reasoning

Definition of Truth

• Truth is defined as when a sentence matches facts to reality.

  • For example, the statement "I am wearing a sweater" is true if it reflects the actual situation.

  • Conversely, the statement "I am wearing a hat" would be false if it does not match reality.

Definition of Belief

• A belief consists of having trust or confidence in someone or something without needing proof.

  • Justification of belief can exist, contrary to stating that belief equates to a lack of evidence.

  • The speaker emphasizes that belief should not be seen only as mere faith or hope, but rather a conviction that may be well-justified by facts.

• Example: Believing that the world is round is supported by extensive evidence.

Conclusion Indicator Words

• Phrases that indicate a conclusion in an argument include:

  • therefore, thus, hence, so,

  • accordingly, consequently.

Premise Indicator Words

• Words that introduce evidence in an argument include:

  • since, because, due to the fact that, given that, because of.

  • Example: "Since he has a runny nose, therefore he must have a cold."

Types of Sentences

Imperative Sentence

• An imperative sentence issues a command.

  • Examples: "Go outside," "Fold the laundry."

Interrogative Sentence

• An interrogative sentence asks a question.

  • Example: "What are you wearing?"

Assertive Sentence

• An assertive sentence makes a declaration that can be evaluated as true or false.

  • Example: "The Earth is the third planet from the sun."

Definition of Deductively Valid Argument

• A deductively valid argument is structured so that if the premises are true, the conclusion must also be true.

  • If a conclusion is true when the premises are true, it illustrates deductive validity.

Definition of Sound Argument

• A sound argument is:

  • A deductively valid argument with all true premises.

  • Importance: Some valid arguments may not be sound if they contain untrue premises.

  • Example of Unsound Argument:

  • Premise: All humans have climbed Mount Everest.

  • Personal Premise: I am a human.

  • Conclusion: Thus, I have climbed Mount Everest.

  • This is valid but not sound due to the false premise.

• Example of Sound Argument:

  • Premise: All dogs are mammals.

  • Premise: Pugs are dogs.

  • Conclusion: Therefore, pugs are mammals (valid and sound).

Definition of Inductively Strong Argument

• An inductively strong argument means if all premises are true, the conclusion is likely to be true but not guaranteed.

• Example:

  • "The rooster has crowed every morning at 6 AM for the past year; therefore, it’s likely to crow tomorrow at 6 AM."

Inductively Weak Argument

• An example might involve unsound reasoning from limited experience.

  • Example:

  • "I won the lottery yesterday, therefore I will win it again next time."

  • This expectation lacks the foundational consistency needed for inductively strong support.

Disjunctive Syllogism

• An argument type structured around disjunction.

  • Example:

  • "I will choose soup or salad. I will not choose soup. Therefore, I will choose salad."

Modus Ponens

• Argument form: If A, then B. A is true; hence B is true.

  • Example:

  • "If I don’t go to work, then I will be happy. I didn’t go to work; therefore, I am happy."

Modus Tollens

• Argument form: If A, then B. Not B means not A.

  • Example:

  • "If I’m in Fullerton, then I’m in California. I am not in California; therefore, I am not in Fullerton."

Chain Argument

• The model uses a chain of conditional statements.

  • Example:

  • If A, then B; if B, then C; hence, if A, then C.

Standard Form of an Argument

• Premises are vertically listed with the conclusion below.

Milgram Study Overview

• A study examining obedience to authority.

• Aimed to understand the tendency of adults to follow harmful orders from authority figures.

• Participants were divided into teachers and learners (confederates).

• 65% of participants complied with authority, administering shocks despite distress from learners.

Zimbardo Study Overview

• Conducted at Stanford University to examine social roles and power dynamics.

• Students were assigned roles of guards and prisoners in a simulated prison.

• Showed rapid escalation to abusive behavior, leading to a halt after just six days instead of intended two weeks.

Three Stages of Cognitive Development

• 1. Dualism: Believing in absolutes.

• 2. Relativism: Recognizing subjective viewpoints.

• 3. Commitment: Committing to beliefs based on reason and evidence.

Confirmation Bias

• A barrier to critical thinking where individuals only seek information that reinforces their existing beliefs.

Effective Communication Components

• Clarity in speaking and writing, active listing, research compilation, flexibility in ideas, and open-minded skepticism.

Collaborative Learning Definition

• Engaging with others in decision-making to find solutions rather than working in isolation.

Creative Problem Solving Definition

• Generating imaginative solutions to complex issues and improvising when necessary.

Benefits of Critical Thinking in Democracy

• Empowers informed voting and sound decision-making in elections, benefiting societal governance.

Personal Benefits of Critical Thinking

• Enhances self-esteem, decision-making, and personal growth through understanding strengths and weaknesses.

Three Stages of Critical Thinking Process

1. Experience: Encountering an event without deep evaluation.

2. Interpretation: Making initial beliefs and claims about the experience.

3. Analysis: Evaluating the initial beliefs and exploring possible alternatives.