 To obtain a negation paradox, let \(\odot\alpha\) be \(\lnot\alpha\), and let \(\mu\) be a sentence intersubstitutable with \(\lnot\mu\) according to  \(\mathcal{T}\).[26]  Then P1 amounts to an instance of ex contradictione quodlibet (or “explosion”), while P2 is a reductio principle.