Take a concrete example. A theory as to the early religious history of the Hebrews, let us say, is put forward upon grounds derived from Semitic philology. Though unacquainted with Semitic philology in particular, I may be able to form some sort of estimate of the cogency of the professed reasoning if I already have an adequate acquaintance with the use and value of philological evidence in parallel cases, say, in the study of Greek antiquities. But if I have no positive acquaintance at all with the use of philology in antiquarian research, it would be the merest impertinence for me to offer any opinion whatever. Footnote 14: What follows must be regarded as a mere outline which awaits subsequent filling up by the more concrete results of Bk II. chap. 1. Footnote 15: For the modern logical doctrine of possibility consult Bradley, _Principles of Logic_, 192-201; Bosanquet, _Logic_, i. chap. 9. Footnote 16: This is—apart from non-essential theological accretions—the principle of Berkeley’s argument for the existence of God (_Principles of Human Knowledge_, §§ 146, 147). Footnote 17: I should explain that I use “feeling” and “apprehension” indifferently for immediate and non-reflective awareness of any psychical content. The exclusive restriction of the term to awareness of pleasure and pain seems to me to rest on a serious mistake in psychology, and I therefore avoid it. Footnote 18: In fact, we shall see in Bk. II. chap. 1 that in virtue of its unity with immediate _feeling_, all experience is essentially connected with purpose. Footnote 19: I take “fact” as equivalent to “what is directly apprehended in a single moment of consciousness.” In a previous work (_The Problem of Conduct_, chap. 1) I used the word in a different sense for “the contents of a _true_ description of experience.” This employment of the word, however, seems at variance with established philosophical usage, and I therefore abandon it as likely to lead to misapprehension. Footnote 20: Of course, the apprehended “content” may itself be a “process,” as is the case in all instances of the apprehension of _change_; but the apprehended process is always distinguishable from the process of apprehension. Footnote 21: We shall see in Bk. II. chap. 1 that the “that” of an experience implies relation to a unique individual interest or purpose. Footnote 22: Of course this is only partly true. As we shall see in the sequel, to “be what it means and mean what it is” is an ideal never _fully_ realised in the structure of any finite piece of reality, precisely because the finite, as its name implies, is never a completely systematic whole. Footnote 23: