It is often claimed that you cannot prove a negative; that is, you cannot prove that some entity does not exist.

Inference to the best explanation is a form of reasoning where one infers that the hypothesis, among competing hypotheses, which best explains the available data is likely true.

This is an informal fallacy which occurs when an initial, seemingly minor, action will inevitably trigger a chain reaction, leading to increasingly severe, undesirable outcomes, often without sufficient evidence for each step.

The American philosopher Edmund Gettier argued in a famous paper in 1963 that we can have a JTB and yet still not have knowledge…

In everyday speech, we say, ‘You make a valid argument’, ‘You have a valid point’, ‘That’s a sound point’, ‘That’s a good argument’, ‘That’s a strong argument’ and so on. This is rather loose-speak.

Affirming the consequent is a logical fallacy whereby the arguer incorrectly concludes the cause (antecedent) because of the effect (consequent).

The branch of Philosophy concerning the nature of knowledge is Epistemology. Philosophers commonly identify three types of knowledge:

Modus tollens (Latin for ‘mode that denies’) is a valid form of logical deduction. It is a conditional form (if-then).