"...racing after thoughts that he could never quite catch..."

Sinclair Lewis, from "The Willow Walk":

He paced into the living room and through the long still hours of the evening he read an ancient book, all footnotes and cross references, about The Numerology of the Prophetic Books, and the Number of the Beast. He tried to make notes for his own book on Revelation - that scant pile of sheets covered with writing in a small finicky hand. Thousands of other sheets he had covered; through whole nights he had written; but always he seemed with tardy pen to be racing after thoughts that he could never quite catch, and most of what he had written he had savagely burned.