Among his many innovations is his principle of wholistic reference, which was later, and probably independently, adopted by Gottlob Frege and by logicians who subscribe to standard first-order logic.
Tema paljude innovatsioonide seas on tema wholistic reference'i printsiip, mille võttis hiljem kasutusele, ilmselt iseseisvalt, Gottlob Frege ja loogikud, kes tegelevad standardse esimest järku loogikaga.