There is … no first person plural to the verb "cogito." Observation, verification, and inference are functions which are perfected only in their independent individual exercise. I am not unmindful of the importance of the corroboration of one mind by another; but such corroboration is valuable only in so far as both minds have reached their results alone. Corroboration implies the absence of collusion. The devotee of the intellect must, then, have the strength to work alone.

The Integrity of the Intellect