The attempt to present an ideal forecast, or outline of the whole of reality, as it would satisfy a mind constituted like ours, an ideal landscape of this sort, is not at all to be confounded with the arrogation of _a priori_ knowledge. _A priori_ knowledge is supposed to be a kind of knowledge, and _knowledge_ of the whole is utterly and confessedly beyond our reach. The phrase _a priori_, too, is objectionable and unfortunate for two reasons. First, as just said, because it has been supposed to be a kind of knowledge. By some theologians men were supposed to possess _a priori_ knowledge of God.[28] Secondly, because the word _a priori_ suggests precedence in time, and our knowledge of the human mind and of its irreducible capacities comes out only in the course of experience. Much that has been called _a priori_, that is implicit in experience, did not become explicit until after prolonged experience. The Greek thinkers before Aristotle doubtless thought in terms of syllogism, but it was not until Greek science had attained a certain ripeness that Aristotle was able to dissect out the logic which had previously been employed more or less unconsciously. Instead, therefore, of using the term _a priori_, which gives rise to the two-fold misapprehension of an _a priori_ knowledge and of temporal precedence, and instead of throwing out the child with the bath, that is, of ignoring the independent part played by our mental constitution in building up experience, and in affording us the conviction of certainty, and of reality, it is highly desirable that a new term be found to take the place of _a priori_. The term “functional finality” suggests itself to me for this purpose.[29] My field is ethics. I am entirely desirous of sticking to my own last, that is, dealing with such concepts as the data of my subject force upon me. I do not wish to trespass, or to seem to trespass, on the domain of my neighbors. Hence in dealing with functional finalities I must deal with them primarily as they appear in the field of ethics, that is, in the domain of the actions and reactions of human beings upon one another. Irreducible _principia_ of ethics are the functional finalities, which prescribe rules for such intercourse, or better which create a scheme of ideal intercourse whereby the conduct of men shall be measured and determined.