Ferrier, J. F. (1854). Proposition XI. Presentation and representation. In J. F. Ferrier, Institutes of metaphysic: The theory of knowing and being (pp. 283-292). Edinburgh, Great Britain: William Blackwood and Sons.
http://dx.doi.org/10.1037/12047-011
That alone can be represented in thought which can be presented in knowledge: in other words, it is impossible to think what it is impossible to know; or, more explicitly, it is impossible to think that of which knowledge has supplied, and can supply, no sort of type. (PsycINFO Database Record (c) 2016 APA, all rights reserved)