Practical Reasoning Midterm 1

System 1

The collection of cognitive processes that feel automatic and effortless but not transparent. These include specialized processes that interpret sensory data and are the source of our impressions, feelings, intuitions, and impulses. (The distinction between the two systems is one of degree, and the two systems often overlap, but it is still useful to distinguish them.)

System 2

The collection of cognitive processes that are directly controlled, effortful, and transparent. (The distinction between the two systems is one of degree, and the two systems often overlap, but it is still useful to distinguish them.)

Cognitive reflection

The habit of checking initial impressions supplied by System 1, and overriding them when appropriate

Cognitive pitfalls

Common, predictable errors in human reasoning. Includes mental glitches uncovered by cognitive psychologists, as well as logical fallacies.

Availability heuristic

Judging the frequency or probability of an event or attribute by asking ourselves how easily we can bring examples to mind from memory.

Belief perseverance

The tendency to continue holding a belief even if its original support has been discredited, and in the face of contrary evidence.

Cognitive illusions

An involuntary error in our thinking or memory due to System 1, which continues to seem correct even if we consciously realize it's not.

Confirmation bias

The tendency to notice or focus on potential evidence for our pre-existing views, and to neglect or discount contrary evidence. Confirmation bias can be present with or without an underlying motive to have the belief in the first place.

Evidence primacy effect

In a process where information is acquired over time, the tendency to give early information more evidential weight than late information. This tendency arises when we develop opinions early on, leading to confirmation bias when interpreting later information, or simply a failure to pay as much attention to it.

Motivated reasoning

Forming or maintaining a belief at least partly because, at some level, we want it to be true. This ability manifests itself in selective standards for belief, seeking and accepting evidence that confirms desired beliefs, and ignoring or discounting evidence that disconfirms them.

Evolutionary mismatch

When a trait or feature evolves in an organism because it is adaptive in one environment, but survives even when the environment changes enough that it's no longer beneficial.

Heuristic

A cognitive shortcut used to bypass the more effortful type of reasoning that would be required to arrive at an accurate answer. Susceptible to systematic and predictable errors.

Suspiciously unexplained set (SUS)

We have this when every relevant consideration concerning a belief seems to go the same way, even when they are independent. This should lead us to worry that at some level our goal isn't just accuracy.

Introspection illusion

The misguided assumption that our own cognitive biases are transparent to us, and as a result, that we can diagnose these biases in ourselves through introspection.

Biased opponent effect

A result of the introspection illusion. Given that we think our own reasoning is unbiased, and that our opponent comes to very different conclusions, we commonly conclude that their reasoning must be biased.

Search stage

The first stage of the reasoning process, where we identify a range of possibilities and any evidence that may support them.

Optional stopping

Allowing the search for evidence to end when convenient; this may skew the evidence if (perhaps unbeknownst to us) we are more likely to stop looking when the evidence collected so far supports our first or favored view.

Restricted search

The tendency not to seek out the full range of alternative views or the full range of evidence that favors each view. Along with biased evaluation, this is an instance of confirmation bias.

Possibility freeze

The tendency to consider only a few possibilities in detail and thereby end up overly confident that no alternative view is correct.

Evaluation stage

The second stage in the reasoning process, when we assess the strength of the potential evidence we’ve gathered.

Considering the opposite

A technique to reduce biased evaluation of evidence, where we ask ourselves either one of two questions: (i) How would I have treated this evidence had it gone the opposite way? or (ii) How would I have treated this evidence if I held the opposite belief?

Decoupling

Separating our prior degree of confidence in a claim from our assessments of the strength of a new argument or a new piece of evidence about that claim.

Updating stage

The third and final stage of the reasoning process, when we revise our degree of confidence appropriately.

Degrees of confidence

Treating beliefs as having different levels of certainty. Just as we can be absolutely sure that X is true or false, we can have every level of certainty in between, e.g., thinking that X is slightly more likely to be true than false, very likely to be true, etc.

Binary belief

Treating beliefs as if they are on/off. For example, we either believe that the cat is on the mat or that the cat is not on the mat, without allowing for different degrees of confidence.

Ambiguity

When it is unclear which word or sentence structure a speaker intends to express because two words look or sound the same. (That is, the same spoken or written forms express different meanings.)

Lexical ambiguity

When it is unclear which of many possible words, which share the same written or spoken form, the speaker is intending to express (e.g., the absent-minded professor was arrested for not finishing his sentence).

Syntactic ambiguity

When it is unclear which sentence structure a speaker intends to express (e.g., man shoots neighbor with machete).

Vagueness

When a word, concept, or distinction has borderline cases (i.e., where it is unclear whether the word/concept/distinction applies).

Bare plurals

The use of a plural noun phrase without a determiner (e.g., “Canadians started laughing” instead of “Some Canadians started laughing”).

Borderline cases

Cases where it is unclear whether a category applies to an individual, and not because we need more facts about the individual (e.g., you might sit on something that seems somewhat like a chair and somewhat like a stool).

Sharp borders fallacy

Assuming that real and useful distinctions with clear cases on either side can't also have borderline cases.

Generality

A matter of how many things an expression applies to.

Argument

A set of statements, one of which, the conclusion, is supposed to follow from the others, the premises.

Premises

The statements expressing the supporting beliefs in an argument; i.e. those intended to support the conclusion.

Premise indicators

Expressions that often signal the presence of a premise (e.g., because, since, as, given that, seeing as).

Conclusion

The statement expressing the belief that our argument is meant to support.

Conclusion indicators

Expressions that often signal the presence of a conclusion (e.g., therefore, so, thus, as a result).

Inference

A single step in a line of reasoning. We take these steps in our reasoning to arrive at a belief, because we take that belief to be supported by other beliefs.

Entailment

One or more premises entail a conclusion when they meet this condition: if the premises were true, the conclusion would also have to be true.

Suppositional strength

A measure of how well the premises connect to the conclusion of an argument. A matter of how much evidence the premises would provide for the conclusion if we suppose them to be true.

Deduction

Arriving at a conclusion on the basis of beliefs that entail it.

Deductive argument

An argument whose premises are presented as entailing its conclusion.

Deductive validity

When an argument’s premises entail its conclusion.

Induction

Arriving at a conclusion on the basis of beliefs that support but do not entail it.

Inductive argument

An argument whose premises are presented as providing support for its conclusion but not entailing it. In these cases, the truth of the premises is not supposed to guarantee the truth of the conclusion with certainty. Instead, the premises are just intended to provide support for the conclusion.

Principle of charity

When interpreting an argument, we should always try to identify the best version of the argument that the author could plausibly have intended.

Implicit premise

A claim that is left unstated but which is taken for granted in making an argument.

Deductive validity

When an argument’s premises entail its conclusion: if the premises were true, the conclusion would have to be true.

Conditional

A statement composed of two sentential clauses joined by if...then.... (Sometimes then is omitted, as in: If Bob starts dancing, I will leave.)

Antecedent/sufficient condition

In a conditional, the clause that expresses the condition—that is, the clause immediately following if.

Consequent/necessary condition

In a conditional, the clause that expresses what is said to follow if the antecedent is true.

Logical form

A structure that can be shared by different arguments; it can be illustrated by replacing certain words or sentences with variables until the argument are the same.

Deductively valid logical form

Every argument with this form is deductively valid.

Modus ponens

Deductively valid logical form where Q is inferred from the premises If P then Q and P.

Modus tollens

Deductively valid logical form where not P is inferred from the premises If P then Q and not Q.

Affirming the consequent

A deductively invalid logical form where P is inferred from the premises If P then Q and Q.

Denying the antecedent

A deductively invalid logical form where not Q is inferred from the premises If P then Q and not P.