folgerichtig

Folgerichtig is a German adjective meaning "logically following" or "entailed." It describes a statement, conclusion, or argument that follows necessarily from given premises under the rules of logic. When a conclusion is folgerichtig, it cannot be false if the premises are true in the same logical system.

In formal logic, folgerichtig denotes logical consequence or entailment. If a set of premises Γ entails a conclusion φ (written Γ ⊨ φ), φ is folgerichtig given Γ. An example is: from the premises "All humans are mortal" and "Sokrates is a human," the conclusion "Sokrates is mortal" is folgerichtig. The term is often used to label arguments whose conclusions follow with necessity from the stated premises, not merely with high probability or plausibility.

In ordinary language, folgerichtig can describe a consequence that naturally and deterministically follows from a situation or set of facts. The word is common in philosophical, mathematical, and logical discourse, but it can also appear in less formal expositions to emphasize that a result follows by necessity rather than by chance.

Etymology-wise, folgerichtig is formed from folgen (to follow) plus the suffix -er + -ichtig, yielding "following-ly" or "logically following." Related concepts include logical entailment, validity, and consequence, which are central to discussions of deductive reasoning and proof.