Animals, then, notwithstanding their wonderful instincts, are deficient in precisely that quality which is the unique criterion of intelligence, namely, versatility. Each species has but one stereotyped ability, outside of which it is woefully stupid and inefficient. “So long,” says Fabre, “as its circumstances are normal the insect’s actions are calculated most rationally in view of the object to be attained” (“The Mason-Bees,” p. 167), but let the circumstances cease to be normal, let them vary never so little from those which ordinarily obtain, and the animal is helpless, while its instinctive predisposition becomes, not merely futile, but often positively detrimental. Thus the instinct, which should, in the normal course of events, guide night-flying moths to the white flowers that contain the life-sustaining nectar of their nocturnal banquets, proves their undoing, when they come into contact with the white lights of artificial illumination. In fact, the fatal fondness of the moth for the candle flame has become in all languages a proverb for the folly of courting one’s own destruction. The animal may employ an exquisitely efficient method in accomplishing its instinctive work, but is absolutely impotent to apply this ingenious method to more than one determinate purpose. Man, however, is not so restricted. He varies at will both his aims and his methods. He can adapt the _same means_ (a pocketknife, for instance) to _different ends_, and, conversely, he can obtain the _same end_ by the use of _different means_ (_e.g._ communicate by mail, or telegraph, or radio). Man, in a word, is _emancipated from limitation to the singular and the concrete_ by virtue of his unique prerogative, reason, or intelligence, the power that enables him _to generalize from the particular and to abstract from the concrete_. This is the secret of his unlimited versatility. This is the basis of his capacity for progress. This is the root of his freedom; for his will seeks happiness in general, happiness in the abstract, and is not, therefore, compelled to choose any particular form or concrete embodiment of happiness, such as this or that style of architecture, this or that form of government, this or that kind of clothing, etc., etc. Teleology is but a material expression of intelligence, and may, therefore, occur in things destitute of intelligence, but versatility is the inseparable concomitant and infallible sign of an inherent and autonomous intelligence. Lacking this quality, instinct, however telic, is obviously not intelligence.