Logic and Reasoning Lecture Notes

Flashcards on Logic and Reasoning

Logic

Reasoning conducted or assessed according to strict principles of validity

Purposeful Reasoning

Goal oriented and often aimed at solving a problem or answering a question

Logical Structure

Relies on rules of logic to ensure consistency and coherence

Evidence Based Reasoning

Uses observations, facts, or assumptions as a foundation

Evaluative Reasoning

Reasoning often includes assessing the validity and reliability of the information

Validity and Soundness

The conclusion logically follows from the premises, an argument is sound if it is valid and all its premises are true

Principle of Non-Contradiction

A statement cannot be both true and false at the same time in the same sense

Principle of the Excluded Middle

A statement is either true or false; there is no middle ground

Occam's Razor

When presented with competing explanations, the simplest explanation is often preferred

Argument

A group of statements, in which some of them are intended to support another statement (the conclusion)

Deductive Argument

An argument whose conclusion necessarily follows from the truth of the premises

Modus Ponens

If P then Q, P, therefore Q

Modus Tollens

If P then Q, Not Q, Therefore not P

Disjunctive Syllogism

P or Q, Not-P, Therefore Q

Leibniz's Law

a is F, a=b, therefore b is F

Inductive Argument

Argument that is intended to provide probabilistic support for its conclusion

Reasoning by Authority

Relies on the credibility of an authority (or expert) to support a conclusion

Causal Argument

Every time I see A, B follows, Therefore A causes B

Argumentation Theory

Analysing arguments to see how a claim is supported by evidence

Abductive Reasoning

Starts with observations and seeks the simplest and most likely explanation

Fallacies

Arguments that are invalid, though often, they appear to be valid on their surface

Equivocation

Using one word-sound to cover two different concepts/word meanings

Question Begging

No persuasive power

Argument From Ignorance

Take it that the absence of positive or negative evidence proves something

Ad Hominem

Consists in an attack on the person rather than the views held by the person

Ad Baculum

Consists of threatening a person unless they agree with the view

Irrelevant Conclusion

Rhetorical figure frequently used in politics

Hasty Generalization

Generalize very hastily forgetting that a generalization is an extremely powerful claim

Non Sequitur

Looks like there are structural reasons for the argument to be valid, but the argument is not valid

Ad Hominem (Fallacy)

Attacking the person instead of addressing the argument itself

Strawman (Fallacy)

Misinterpreting an argument to make it easier to attack

Circular Reasoning (Fallacy)

Assuming what you are trying to prove, using the conclusion as premise to support itself

Appeal to Ignorance (Fallacy)

Claiming something is true because it hasn’t been proven as false (or vice versa)

False Dichotomy (Fallacy)

Presenting only two options when more exist

Hasty Generalization (Fallacy)

Drawing a broad conclusion from insufficient evidence