Paths Through the Fog: A Comparative Analysis of Ten Philosophical Logics for Vagueness

Vagueness challenges the boundaries of classical logic by exposing how incremental changes—like adding a single hair to a bald man—lead one to paradoxical conclusions. Without claiming exhaustivity, this study compares ten philosophical logics for vagueness —nine non-classical: trivaluationism, fuzzy logic, supervaluationism, non-numerical degree-based, probabilism, fuzzy plurivaluationism, “truer”-based, non-transitivism, compatibilism, and one classical: epistemicism—each offering a distinct way to replace or refine classical logic. The guiding question is: What minimal modifications allow us to preserve most workings of classical logic while embracing the graduality and inexactitude characteristic of vagueness? Through a comparative method, the study explores four axes: (1) truth values, (2) operators and truth-functionality, (3) semantics, (4) truth, validity and the Sorites paradox, and concludes with comparative tables and brief evaluative remarks.