 Curry-Paradox Lemma Suppose that theory \(\mathcal{T}\) and sentence \(\pi\) are such that (i) there is a Curry sentence for \(\pi\) and \(\mathcal{T}\), (ii) all instances of the identity rule (Id) \(\alpha \vdash_{\mathcal{T}} \alpha\) hold, and (iii) the conditional \({\rightarrow}\) satisfies both of the following principles: