When you strive to get the purest conceptions you can of Firstness, Secondness, and Thirdness, thinking of quality, reaction, and mediation – what you are striving to apprehend is pure Firstness, the Firstness of Secondness – that is what Secondness is, of itself – and the Firstness of Thirdness.
http://www.commens.org/dictionary/entry/quote-csps-lowell-lectures-1903-2nd-part-3rd-draught-lecture-iii-0