Philosophical razor

In philosophy, a razor is a principle or rule of thumb that allows one to eliminate (shave off) unlikely explanations for a phenomenon, or avoid unnecessary actions.^[1]

• Alder's razor (also known as Newton's flaming laser sword): If something cannot be settled by experiment or observation, then it is not worthy of debate.^[2]
• Grice's razor (also known as Guillaume's razor): As a principle of parsimony, conversational implicatures are to be preferred over semantic context for linguistic explanations.^[3]
• Hanlon's razor: Never attribute to malice that which can be adequately explained by stupidity.^[4]
• Hitchens' razor: That which can be asserted without evidence can be dismissed without evidence.^[5]
• Hume's guillotine: What ought to be cannot be deduced from what is; prescriptive claims cannot be derived solely from descriptive claims, and must depend on other prescriptions. "If the cause, assigned for any effect, be not sufficient to produce it, we must either reject that cause, or add to it such qualities as will give it a just proportion to the effect."^[6]
• Occam's razor: Explanations that require fewer unjustified assumptions are more likely to be correct; avoid unnecessary or improbable assumptions.
• Popper's falsifiability criterion: For a theory to be considered scientific, it must be falsifiable.^[7]
• Sagan standard: Positive claims require positive evidence, extraordinary claims require extraordinary evidence.^[8]

See also

• Philosophy portal
• Psychology portal
• Science portal

• Abductive reasoning – Inference seeking the simplest and most likely explanation
• Duck test – Classification based on observable evidence
• Law of the instrument – Over-reliance on a familiar tool
• Explanatory power – Ability of a theory to explain a subject
• Marcello Truzzi § "Extraordinary claims"
• Morgan's Canon – Law of parsimony in comparative (animal) psychology
• Morton's fork – False dilemma in which contradictory observations lead to the same conclusion
• Russell's teapot – Analogy formulated by Bertrand Russell to illustrate that the burden of proof lies upon a person making empirically unfalsifiable claims
• Occam's razor § Anti-razors
• Zebra (medicine) – Exotic diagnosis in medicine which is usually unnecessary and wrong