“…Not surprisingly, different forms of reasoning play a central part in mathematics education research. A search for the term "reasoning" in Lerman's (2020) most recent 916-pages long Encyclopedia of Mathematics Education, which I assume to present contemporary and influential theories in the discipline, yields entries on "deductive reasoning" (Harel & Weber, 2020), "mathematical proof, argumentation, and reasoning" (Hanna, 2020), and "quasi-empirical reasoning" (Sriraman & Mousoulides, 2020), as well as further mentions of more than 30 other forms of reasoning, including algebraic reasoning, diagrammatic reasoning, functional reasoning, geometric reasoning, inductive reasoning, mathematical reasoning, multiplicative reasoning, scientific reasoning, and statistical reasoning. 2 Although we find "mathematical reasoning" alone mentioned in 28 of the 216 entries of the Encyclopedia, it remains unclear what is meant by the term.…”