section_path: Areas of research/Epistemology of logic
section_name: Epistemology of logic
paragraph_text: Epistemology of logic
  
  The epistemology of logic studies how one knows that an argument is valid or that a proposition is logically true. This includes questions like how to justify that modus ponens is a valid rule of inference or that contradictions are false. The traditionally dominant view is that this form of logical understanding belongs to knowledge a priori. In this regard, it is often argued that the mind has a special faculty to examine relations between pure ideas and that this faculty is also responsible for apprehending logical truths. A similar approach understands the rules of logic in terms of linguistic conventions. On this view, the laws of logic are trivial since they are true by definition: they just express the meanings of the logical vocabulary.
  
  Some theorists, like Hilary Putnam and Penelope Maddy, object to the view that logic is knowable a priori. They hold instead that logical truths depend on the empirical world. This is usually combined with the claim that the laws of logic express universal regularities found in the structural features of the world. According to this view, they may be explored by studying general patterns of the fundamental sciences. For example, it has been argued that certain insights of quantum mechanics refute the principle of distributivity in classical logic, which states that the formula A ∧ (B ∨ C) {\displaystyle A\land (B\lor C)} is equivalent to (A ∧ B) ∨ (A ∧ C) {\displaystyle (A\land B)\lor (A\land C)}. This claim can be used as an empirical argument for the thesis that quantum logic is the correct logical system and should replace classical logic.