The second major discovery, discernible in his work but confirmed beyond doubt in his library, was that McCarthy was a genius-level intellectual polymath with an insatiable curiosity. His interests ranged from quantum physics, which he taught himself by reading 190 books on the notoriously challenging subject, to whale biology, violins, obscure corners of French history in the early Middle Ages, the highest levels of advanced mathematics and almost any other subject you can name.

Al-Ghazali (c. 1058 – 19 December 1111; ٱلْغَزَّالِيُّ), full name Abū Ḥāmid Muḥammad ibn Muḥammad aṭ-Ṭūsiyy al-Ġazzālīy (أَبُو حَامِدٍ مُحَمَّدُ بْنُ مُحَمَّدٍ ٱلطُّوسِيُّ ٱلْغَزَالِيُّ),[a] and known in Persian-speaking countries as Imam Muhammad-i Ghazali (Persian: امام محمد غزالی) or in Medieval Europe by the Latinized as Algazelus or Algazel, was a Persian Muslim polymath.