was the first one
... that Ṭūsī was the first one to recognize that, if a declarative sentence that declares itself being false, is false, this does not necessitate it being true?
... that <a href="./Nasir_al-Din_al-Tusi" id="mwC2A" rel="mw:WikiLink" title="Nasir al-Din al-Tusi">Ṭūsī</a> <b id="mwC2E"><a href="./Liar_paradox_in_early_Islamic_tradition" id="mwC2I" rel="mw:WikiLink" title="Liar paradox in early Islamic tradition">was the first one</a></b> to recognize that, if a <a class="mw-redirect" href="./Declarative_sentence" id="mwC2M" rel="mw:WikiLink" title="Declarative sentence">declarative sentence</a> that <a href="./Self-reference" id="mwC2Q" rel="mw:WikiLink" title="Self-reference">declares itself</a> being false, is false, this does not necessitate it being true?