The ground on which a discrimination between facts is habitually made changes as the interest from which the facts are habitually viewed changes. Those features of the facts at hand are salient and substantial upon which the dominant interest of the time throws its light. Any given ground of distinction will seem insubstantial to any one who habitually apprehends the facts in question from a different point of view and values them for a different purpose. The habit of distinguishing and classifying the various purposes and directions of activity prevails of necessity always and everywhere; for it is indispensable in reaching a working theory or scheme of life. The particular point of view, or the particular characteristic that is pitched upon as definitive in the classification of the facts of life depends upon the interest from which a discrimination of the facts is sought. The grounds of discrimination, and the norm of procedure in classifying the facts, therefore, progressively change as the growth of culture proceeds; for the end for which the facts of life are apprehended changes, and the point of view consequently changes also. So that what are recognised as the salient and decisive features of a class of activities or of a social class at one stage of culture will not retain the same relative importance for the purposes of classification at any subsequent stage.
But the change of standards and points of view is gradual only, and it seldom results in the subversion or entire suppression of a standpoint once accepted. A distinction is still habitually made between industrial and non-industrial occupations; and this modern dis-
