Answer:

axiom

AnswerCrossword Clue
AXIOMMurphy's Law, for one
AXIOM"Caveat emptor," for one
AXIOMGolden rule, e.g.
AXIOMSaw
AXIOMProposition assumed without proof
AXIOMAdage
AXIOMLogic truth
AXIOMGiven in philosophy class?
AXIOMIt's self-evident
AXIOMOld saw
AXIOMAccepted truth
AXIOMMath proposition that needs no proof
AXIOMSelf-evident truth
AXIOMUniversal principle
AXIOMGeometry truth
AXIOMIt's accepted as true without proof
AXIOMGeometry basic
AXIOMAccepted postulate
AXIOMAccepted principle
AXIOMGeometry postulate
AXIOMTruth held to be self-evident
AXIOMGeometry staple
AXIOMAssumed truth
AXIOMTruthful principle
AXIOMUniversally accepted principle
AXIOM"If it ain't broke, don't fix it," e.g.
AXIOM"What goes up must come down," e.g.
AXIOMTruism
AXIOM"There's no such thing as a free lunch," e.g.
AXIOMIt requires no proof
AXIOMUniversally accepted statement
AXIOMAccepted statement
AXIOMAssumed truth, in logic
AXIOMAccepted rule
AXIOMWords to live by
AXIOMStatement that needs no proof
AXIOMWe hold this truth to be self-evident
AXIOMGeometric truth
AXIOMPrinciple accepted as true
AXIOMSelf-evident statement