The best-known syntactic account of the logical constants is inferentialism . Following Wittgenstein’s thought that meaning is use, inferentialists argue that meanings of expressions are given by introduction and elimination rules. This is especially plausible for the logical constants, where standard presentations divide inference rules in just this way. But not just any rules will do, as we’ve learnt from Prior’s famous example of tonk, and the usual extra constraint is harmony. Where does this leave identity? It’s usually taken as a logical constant but it doesn’t seem harmonious: standardly, the introduction rule (reflexivity) only concerns a subset of the formulas canvassed by the elimination rule (Leibniz’s law). In response, Read [5, 8] and Klev [3] amend the standard approach. We argue that both attempts fail, in part because of a misconception regarding inferentialism and identity that we aim to identify and clear up.

逻辑常数最著名的句法说明是推理主义。遵循维特根斯坦的意义即使用的思想，推论主义者认为表达式的意义是由引入和消除规则给出的。这对于逻辑常量尤其合理，其中标准表示就是以这种方式划分推理规则。但不是任何规则都可以，正如我们从Prior 著名的tonk例子中学到的那样，通常的额外约束是和声. 这在哪里留下身份？它通常被视为一个逻辑常数，但它似乎并不和谐：标准地，引入规则（自反性）仅涉及消除规则（莱布尼茨定律）所讨论的公式的一个子集。作为回应，Read [5, 8] 和 Klev [3] 修改了标准方法。我们认为这两种尝试都失败了，部分原因是我们旨在识别和澄清对推理和身份的误解。