Note 290 — Chapter X · (continued 2)

The contrast between the Monism thus reached and our own psychological point of view can be exhibited schematically thus, the terms in squares standing for what, for us, are the ultimate irreducible data of psychological science, and the vincula above it symbolizing the reductions which post-Kantian idealism performs:

These reductions account for the ubiquitousness of the 'psychologist's fallacy (bk. ii, ch. i, p. 32) in the modern monistic writings. For us it is an unpardonable logical sin, when talking of a thought's knowledge (either of an object or of itself), to change the terms without warning, and, substituting the psychologist's knowledge therefor, still make as if we were continuing to talk of the same thing. For monistic idealism, this is the very enfranchisement of philosophy, and of course cannot be too much indulged in.