Ch 3: Clarity

Ambiguity

When it is unclear which word or sentence structure a speaker intends to express due to similar forms expressing different meanings.

Bare plurals

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

Borderline cases

Instances where it is unclear if a category applies to an individual, not due to lack of facts.

Conclusion

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

Conclusion indicators

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

Deduction

Arriving at a conclusion based on beliefs that entail it.

Deductive argument

An argument whose premises are presented as entailing its conclusion.

Deductive validity

An argument is deductively valid when its premises entail its conclusion.

Directly perceptual beliefs

Beliefs supported directly by perception rather than by other beliefs.

Entailment

When one or more premises entail a conclusion, meaning if the premises are true, the conclusion must also be true.

Generality

The extent to which an expression applies to many things, distinct from ambiguity and vagueness.

Implicit premise

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

Induction

Arriving at a conclusion based on beliefs that support but do not entail it.

Inductive argument

An argument whose premises provide support for its conclusion but do not guarantee its truth.

Inference

A single step in reasoning that leads to a belief supported by other beliefs.

Interim conclusion

A conclusion supported by some premises that also supports a further conclusion.

Lexical ambiguity

When it is unclear which of many possible words a speaker intends to express.

Premise indicators

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

Premises

Statements expressing supporting beliefs in an argument intended to support the conclusion.

Principle of charity

The practice of identifying the best version of an argument that the author could plausibly have intended.

Self-evident beliefs

Beliefs that are obviously true and do not require support (e.g., “1+1=2”).

Sharp borders fallacy

The assumption that distinctions with clear cases cannot have borderline cases.

Standard form

A representation of an argument in an ordered series of declarative sentences with labeled premises and conclusions.

Suppositional strength

A measure of how well the premises connect to the conclusion of an argument.

Syntactic ambiguity

When it is unclear which sentence structure a speaker intends to express.

Vagueness

When a word, concept, or distinction has borderline cases where its application is unclear.

Generality

An expression's generality is a matter of how many things it applies to. Generality is distinct from both ambiguity and vagueness.