not merely subjective. They are built of materials from the outside world and they represent conditions existing in that world. Only in so far as they do this are they truths. But not to dwell on the psychology of the subject, what here concerns us is the fact that every such act of the mind is attended with an intense satisfaction. It seems almost a mockery to call it a pleasure, so far above all those experiences commonly called pleasures does it rise, but it certainly belongs to the same great psychic group as all other pleasures, and our language lacks the appropriate term to characterize it.
The power to discover truth exists in all minds, but in most, it must be confessed, it is very feeble, while comparatively few ever attempt to exercise it. This is, therefore, in the present condition of our race, a limited source of gratification, but it is capable of indefinite extension, and makes up in its sterling worth what it lacks in range and universality. Without it there would be no science, for science rests upon the discovery of truth and not merely upon the accumulation of facts. The real moral progress of the world is due to science, and therefore this motive may be regarded as the most altruistic of all.
It thus appears that as a rule those desires whose satisfaction is most important from the standpoint of nature or function are least important from the standpoint of the individual or feeling. That is to say, the more essential they are to life the less pleasure they yield, and vice versa. The first of these qualities may be called necessity, the second utility, and, thus defined, the necessity of a desire stands in an inverse ratio to its utility.
The several classes of human pleasures, therefore, as treated above, arranged in the descending order of their necessity and ascending order of their utility, will stand as follows: 1. Reproductive. 2. Nutritive. 3. Æsthetic. 4. Emotional. 5. Moral. 6. Intellectual.
I have dwelt thus at length upon the scale of pleasures because, as we shall now perceive, they constitute the basis of all human activity. It is upon this affective part of mind that sociology rests, and not upon its intellectual part. Sociology is
