Since nothing can be concluded from a comparison of ‘This is good’ with, let us say, ‘This is sought by an impulse belonging to a dominant group’, let us see whether light can be gained by considering analogous instances in which special distinct ideas have for a time been thought indispensable only to yield later to analysis and substitution. The case of Beauty is perhaps too closely related to that of Good for our purpose. Those who can persuade themselves that Good is an unique irreducible entity might believe the same of Beauty. An episode in the theory of the tides is more instructive. It was once thought that the moon must have a peculiar Affinity with water: When the moon is full the tides are higher. Clearly the seas swell in sympathy with the increase of the moon. The history of science is full of mysterious unique entities which have gradually evaporated as explanation advanced. The struggles of economists with ‘utility’, of mathematical philosophers with ‘points’ and ‘instants’, of biologists with ‘entelechies’, and the adventures of psycho-analysts with ‘the libido’ and ‘the collective unconscious’ are instances in point. At present theoretical psychology in particular is largely made up of the manipulation of similar suspects. The Act of Judgment, the relation of Presentation, Immediate Awareness, Direct Inspection, the Will, Feeling, Assumption, Acceptance, are only a few of the provisional ultimates introduced for convenience of discussion. Some of them may in the end prove to be indispensable, but meanwhile they are not, to prudent people, more than symbolic conveniences; theories dependent upon them must not be allowed to shut off from investigation fields which may be fruitful. [15] Throughout this discussion ‘experience’ will be used in a wide sense to stand for any occurrence in the mind. It is equivalent to ‘mental state, or process.’ The term has often unfortunate suggestions of passiveness and of consciousness, but many of the ‘experiences’ here referred to would ordinarily be called ‘actions’ and have parts which are not conscious and not accessible to introspection as important as those which are. [16] A chief advocate of this view is Dr G. E. Moore, whose _Principia Ethica_ and _Ethics_ contain brilliant statements of the position. [17] Cf. F. Brentano, _The Origin of the Knowledge of Right and Wrong_, pp. 12, 46.