D-265 Critical Thinking: Reason and Evidence
Notes
Contents
Section 1................................................................................................................................................................................ 3
Lesson 1.1: Critical Thinking.........................................................................................................................................3
Lesson 1.2: Propositions...............................................................................................................................................4
Lesson 1.3: Complex Propositions................................................................................................................................5
Lesson 1 Quiz: Basic Components of Propositions.......................................................................................................7
Lesson 2.1: Distinguishing Between Premises and Conclusions (1/2)...........................................................................8
Lesson 2.1: Distinguishing Between Premises and Conclusions (1/2)...........................................................................8
Lesson 2.2: Distinguishing Between Premises and Conclusions (2/2).........................................................................10
Lesson 2: Quiz and Summary.......................................................................................................................................12
Lesson 3.1: Distinguishing between Arguments and Non-Arguments........................................................................13
Lesson 4.1 Validity or Strength of Arguments.............................................................................................................15
Lesson 4.2 Truth, Validity and Soundness Deductive Arguments................................................................................16
Lesson 4.3 Truth, Strength, and Cogency – Inductive Arguments...............................................................................18
Lesson 4: Quiz and Summary......................................................................................................................................20
Lesson 5.1 Fallacies.....................................................................................................................................................21
Lesson 5.2: Examples of Fallacies...............................................................................................................................22
Section 1 quiz.............................................................................................................................................................. 24
Section 2: Evaluating Arguments and Evidence: Source Credibility.....................................................................................28
Lesson 1.1: Sources of Information............................................................................................................................28
Lesson 1.2: Specific Sources.......................................................................................................................................29
Lesson 1 Quiz and Summary........................................................................................................................................30
Section 3 Identifying Bias and Its Impact.............................................................................................................................30
Lesson 1.1: Confirmation Bias....................................................................................................................................30
Lesson 1 Quiz: Confirmation Bias................................................................................................................................31
Lesson 2.1: Cognitive Bias.........................................................................................................................32
Lesson 2.2 Mental Heuristics.....................................................................................................................33
Lesson 2 Quiz and Summary – Cognitive Bias............................................................................35
Lesson 3.1: Statistical Generalization...................................................................................................36
Lesson 3.2: Statistical Generalization....................................................................................................37
Lesson 3 Quiz: Statistical Generalization..............................................................................................39
Lesson 4.1: Bias, Reasoning, and Decision-making..........................................................................40
1
, Lesson 4.2: Reasoning and Decision-making......................................................................................42
Lesson 4 Quiz: Bias, Reasoning, Decision-making....................................................................................43
Section 4: Making A Claim..................................................................................................................................................44
Lesson 1.1: Fallacies of Relevance (1/2)......................................................................................................44
Lesson 1.2: Fallacies of Relevance (2/2)......................................................................................................46
Lesson 1.3: More Fallacies of Relevance (1/2)...............................................................................................47
Lesson 1.4: More Fallacies of Relevance (2/2)...........................................................................................48
Lesson 1.5: Still More Fallacies of Relevance (1/2)...................................................................................49
Lesson 1.6: Still More Fallacies of Relevance (2/2)...................................................................................53
Lesson 1 Quiz: Fallacies of Relevance...........................................................................................................54
Lesson 2.1: Weak Induction (1/2)...................................................................................................................56
Lesson 2.2: Weak Induction (2/2)...................................................................................................................58
Lesson 2.3: More Fallacies of Weak Induction (1/3).........................................................................59
Lesson 2.4: More Fallacies of Weak Induction (2/3).........................................................................61
Lesson 2.5: More Fallacies of Weak Induction (3/3).........................................................................62
Lesson 2 Quiz: Fallacies of Weak Induction.........................................................................................63
Lesson 3.1: Fallacies of Presumption.....................................................................................................64
Lesson 3 Quiz: Fallacies of Presumption...............................................................................................66
Lesson 4.1: Argument Mapping Basics (1/2).......................................................................................67
Lesson 4.2: Argument Mapping Basics (2/2).......................................................................................69
Lesson 4.3: Terminology (1/2)..................................................................................................................74
Lesson 4.4: Terminology (2/2)..................................................................................................................75
Lesson 4 Quiz: Argument Mapping.........................................................................................................79
Lesson 5: Missing Assumptions................................................................................................................81
Lesson 5.2: Mapping Hidden Assumptions...........................................................................................85
Lesson 5 Quiz and Summary.....................................................................................................................87
Lesson 6.1: Beginning to Evaluate Arguments...................................................................................88
Lesson 6 Quiz and Summary.....................................................................................................................91
2
,Section 1
Lesson 1.1: Critical Thinking
To engage in critical thinking is to engage in self-critical, self-reflective, self-aware
thinking and reasoning—thinking and reasoning aimed at self-improvement, at
truth, and at careful, deliberate, proper patterns of reasoning.
Critical – means to be reflective, careful, or attentive to potential errors.
3
, • Being curious and thinking creatively: not believing things are simple and
settled, being willing to go the next step and think about all of the possible
positions and arguments before settling into a position.
• Separating the thinker from the position: being able to discuss a position without
attacking or judging the person holding the position, without getting caught
up in our own attachment to the position or its antithesis, and without
having our identities wrapped up in a particular viewpoint or opinion.
• Knowing oneself enough to avoid biases and errors of thought: being aware of
the flawed patterns of reasoning we are disposed to engage in, being aware of
cognitive biases and mental heuristics (rough rules that work well enough to
survive but don't work in many cases) that we're prone as a species to have,
all in the interest of counteracting these biases and flaws.
• Having intellectual honesty, humility, and charity: very important:
being honest about what we know and how we know it, what evidence we have
and what questions are not yet settled; being humble in recognizing the vast
number of things we don't yet know or understand and in recognizing how
very difficult it is to truly know anything at all and so recognizing that the
standards are high and we, most of the time, don't meet them (and that's
okay); and being charitable or having the disposition to attribute the best
intentions and most sophisticated positions and arguments that we can
imagine to our opponents in arguments.
• Understanding arguments, reasons, and evidence: thinking carefully about
thinking,
about arguments and positions.
Lesson 1.2: Propositions
Propositions are statements that can be true or false. This is the fundamental
concept. Take the time to understand it clearly. You can agree or disagree with
them, they can be argued about whether they are right or wrong.
If a sentence can be true or false, then it expresses a proposition. Not all sentences
express propositions.
Non-propositions - are not statements about matters of fact (or fiction). They do not
make a claim that can be true or false. Would not make any sense to disagree with
them. You cannot argue with them. You cannot disagree with them.
They do these things:
o Exhort: Let's go get dinner! Let’s go hiking on Tuesday!
o Command: Go to the store later to buy me some cheese. Don't do that.
4
Notes
Contents
Section 1................................................................................................................................................................................ 3
Lesson 1.1: Critical Thinking.........................................................................................................................................3
Lesson 1.2: Propositions...............................................................................................................................................4
Lesson 1.3: Complex Propositions................................................................................................................................5
Lesson 1 Quiz: Basic Components of Propositions.......................................................................................................7
Lesson 2.1: Distinguishing Between Premises and Conclusions (1/2)...........................................................................8
Lesson 2.1: Distinguishing Between Premises and Conclusions (1/2)...........................................................................8
Lesson 2.2: Distinguishing Between Premises and Conclusions (2/2).........................................................................10
Lesson 2: Quiz and Summary.......................................................................................................................................12
Lesson 3.1: Distinguishing between Arguments and Non-Arguments........................................................................13
Lesson 4.1 Validity or Strength of Arguments.............................................................................................................15
Lesson 4.2 Truth, Validity and Soundness Deductive Arguments................................................................................16
Lesson 4.3 Truth, Strength, and Cogency – Inductive Arguments...............................................................................18
Lesson 4: Quiz and Summary......................................................................................................................................20
Lesson 5.1 Fallacies.....................................................................................................................................................21
Lesson 5.2: Examples of Fallacies...............................................................................................................................22
Section 1 quiz.............................................................................................................................................................. 24
Section 2: Evaluating Arguments and Evidence: Source Credibility.....................................................................................28
Lesson 1.1: Sources of Information............................................................................................................................28
Lesson 1.2: Specific Sources.......................................................................................................................................29
Lesson 1 Quiz and Summary........................................................................................................................................30
Section 3 Identifying Bias and Its Impact.............................................................................................................................30
Lesson 1.1: Confirmation Bias....................................................................................................................................30
Lesson 1 Quiz: Confirmation Bias................................................................................................................................31
Lesson 2.1: Cognitive Bias.........................................................................................................................32
Lesson 2.2 Mental Heuristics.....................................................................................................................33
Lesson 2 Quiz and Summary – Cognitive Bias............................................................................35
Lesson 3.1: Statistical Generalization...................................................................................................36
Lesson 3.2: Statistical Generalization....................................................................................................37
Lesson 3 Quiz: Statistical Generalization..............................................................................................39
Lesson 4.1: Bias, Reasoning, and Decision-making..........................................................................40
1
, Lesson 4.2: Reasoning and Decision-making......................................................................................42
Lesson 4 Quiz: Bias, Reasoning, Decision-making....................................................................................43
Section 4: Making A Claim..................................................................................................................................................44
Lesson 1.1: Fallacies of Relevance (1/2)......................................................................................................44
Lesson 1.2: Fallacies of Relevance (2/2)......................................................................................................46
Lesson 1.3: More Fallacies of Relevance (1/2)...............................................................................................47
Lesson 1.4: More Fallacies of Relevance (2/2)...........................................................................................48
Lesson 1.5: Still More Fallacies of Relevance (1/2)...................................................................................49
Lesson 1.6: Still More Fallacies of Relevance (2/2)...................................................................................53
Lesson 1 Quiz: Fallacies of Relevance...........................................................................................................54
Lesson 2.1: Weak Induction (1/2)...................................................................................................................56
Lesson 2.2: Weak Induction (2/2)...................................................................................................................58
Lesson 2.3: More Fallacies of Weak Induction (1/3).........................................................................59
Lesson 2.4: More Fallacies of Weak Induction (2/3).........................................................................61
Lesson 2.5: More Fallacies of Weak Induction (3/3).........................................................................62
Lesson 2 Quiz: Fallacies of Weak Induction.........................................................................................63
Lesson 3.1: Fallacies of Presumption.....................................................................................................64
Lesson 3 Quiz: Fallacies of Presumption...............................................................................................66
Lesson 4.1: Argument Mapping Basics (1/2).......................................................................................67
Lesson 4.2: Argument Mapping Basics (2/2).......................................................................................69
Lesson 4.3: Terminology (1/2)..................................................................................................................74
Lesson 4.4: Terminology (2/2)..................................................................................................................75
Lesson 4 Quiz: Argument Mapping.........................................................................................................79
Lesson 5: Missing Assumptions................................................................................................................81
Lesson 5.2: Mapping Hidden Assumptions...........................................................................................85
Lesson 5 Quiz and Summary.....................................................................................................................87
Lesson 6.1: Beginning to Evaluate Arguments...................................................................................88
Lesson 6 Quiz and Summary.....................................................................................................................91
2
,Section 1
Lesson 1.1: Critical Thinking
To engage in critical thinking is to engage in self-critical, self-reflective, self-aware
thinking and reasoning—thinking and reasoning aimed at self-improvement, at
truth, and at careful, deliberate, proper patterns of reasoning.
Critical – means to be reflective, careful, or attentive to potential errors.
3
, • Being curious and thinking creatively: not believing things are simple and
settled, being willing to go the next step and think about all of the possible
positions and arguments before settling into a position.
• Separating the thinker from the position: being able to discuss a position without
attacking or judging the person holding the position, without getting caught
up in our own attachment to the position or its antithesis, and without
having our identities wrapped up in a particular viewpoint or opinion.
• Knowing oneself enough to avoid biases and errors of thought: being aware of
the flawed patterns of reasoning we are disposed to engage in, being aware of
cognitive biases and mental heuristics (rough rules that work well enough to
survive but don't work in many cases) that we're prone as a species to have,
all in the interest of counteracting these biases and flaws.
• Having intellectual honesty, humility, and charity: very important:
being honest about what we know and how we know it, what evidence we have
and what questions are not yet settled; being humble in recognizing the vast
number of things we don't yet know or understand and in recognizing how
very difficult it is to truly know anything at all and so recognizing that the
standards are high and we, most of the time, don't meet them (and that's
okay); and being charitable or having the disposition to attribute the best
intentions and most sophisticated positions and arguments that we can
imagine to our opponents in arguments.
• Understanding arguments, reasons, and evidence: thinking carefully about
thinking,
about arguments and positions.
Lesson 1.2: Propositions
Propositions are statements that can be true or false. This is the fundamental
concept. Take the time to understand it clearly. You can agree or disagree with
them, they can be argued about whether they are right or wrong.
If a sentence can be true or false, then it expresses a proposition. Not all sentences
express propositions.
Non-propositions - are not statements about matters of fact (or fiction). They do not
make a claim that can be true or false. Would not make any sense to disagree with
them. You cannot argue with them. You cannot disagree with them.
They do these things:
o Exhort: Let's go get dinner! Let’s go hiking on Tuesday!
o Command: Go to the store later to buy me some cheese. Don't do that.
4
