I will venture to guess that you will be surprised to learn […] how true it is that a habit can be acquired by imaginary practice. Out of such considerations, which turn, as if upon a pivot, about the idea that a thought is nothing but a habit connected with a sign, one can build up quite a little philosophy which is what I meant by “pragmatism.”
http://www.commens.org/dictionary/entry/quote-letter-j-h-kehler-6