epithet instinctive is frequently employed in a wide sense to include acquired habits of action, original dispositions to any form of movement, whether random or purposive, and also purely reflex actions devoid of all antecedent or concomitant consciousness. In modern Psychology there is a tendency to confine the adjective to conscious acts which are connate or unlearned, complex, and purposive in character. Strictly speaking, Instinct is not a continuous impulse towards a special mode of action, but an aptitude by which this impulsive action is directed or guided.

The Scholastic writers classed this faculty among the internal senses, under the title of the Vis Estimativa. Conceived according to their view and in harmony with common usage, Instinct may perhaps be best defined as a natural aptitude which guides animals in the unreflecting performance of complex acts useful for the preservation of the individual or of the species. In the Scholastic system the Vis Estimativa is a property of the sentient soul, analogous though inferior to rational judgment in man. It is of an organic character, but involves more than the direct response of the special senses. It does not merely distinguish between pleasant and painful impressions, but guides the animal in a series of movements remotely serviceable to its nature. The lamb, St. Thomas observes, does not flee because the colour or form of the wolf is disagreeable, and the bird does not collect twigs for its nest because they are attractive in themselves; but both animals are endowed with a faculty which under appropriate conditions is excited by these phenomena to guide them in the execution of an operation ulteriorly beneficial to their nature. Yet neither has a consciousness of the formal relation of such an act to the end to be attained; neither may have had any previous personal acquaintance with that end; and neither is Îed to the act by a process of reasoning.

The essential features of Instinct are well explained in the following passage: "The character which above all distinguishes instinctive actions from those that may be called intelligent or rational, is that they are not

the result of imitation and experience; that they are always executed in the same manner, and, to all appearance, without being preceded by the foresight either of their result or of their utility. Reason supposes a judgment and a choice: instinct, on the contrary, is a blind impulse which naturally impels the animal to act in a determinate manner : its effects may sometimes be modified by experience, but they never depend on it." Again: "One of the phenomena fittest to give a clear idea of what ought to be understood by Instinct is that which is presented to us by certain insects when they lay their eggs. Those animals will never see their progeny, and can have no acquired notion of what their eggs will become; and yet they have the singular habit of placing beside each of those eggs a supply of elementary matter fit for nourishing the larva it will produce, and that even when that food differs entirely from their own, and when the food they thus deposit would be useless for themselves. No sort of reasoning can guide them in doing this, for if they had the faculty of reason, facts would be wanting them to arrive at such conclusions, and they must needs act blindly." Such facts, which might be multiplied indefinitely, prove that animal "intelligence" is different, not in degree, but in kind from human intellect.

The origin of instinct, together with the formation of organs, has ever been one of the most insuperable difficulties to those who deny the existence of an Intelligent Author of the Universe. Mr. Herbert

6 Milne-Edwards, Zoologie, § 319.

7 Id. § 327. Cf. Janet's Final Causes, pp. 86, 87. "The young female wasp (sphex), without maternal experience, will seize caterpillars or spiders, and stinging them in a certain definite spot, paralyze and deprive them of all power of motion (and probably also of sensation), without depriving them of life. She places them thus paralyzed in her nest with her eggs, so that the grubs, when hatched, may be able to subsist on a living prey, unable to escape from or resist their defenceless and all but powerless destroyers. Now, it is absolutely impossible that the consequences of its actions can have been intellectually apprehended by the parent wasp. Had she Reason without her natural Instinct she could only learn to perform such actions through experience." (Mivart, Lessons from Nature, pp. 201, 202. Cf. also On Truth, c. xxiii.)

Spencer, and thorough-going evolutionists generally, seek to explain instinct as hereditary experience. It is described sometimes as "lapsed intelligence," and sometimes as a "habit acquired by Natural Selection" during the history of the race. It is indeed possible that some native tendencies might be accounted for in the former way. Certain actions intelligently and frequently performed might conceivably pass into organic habits capable of hereditary transmission; and it is also possible that advantageous modifications might be effected in existing instincts by means of Natural Selection. But, whilst we readily admit so much, we affirm that it is futile and absurd to seek to explain instinct in general in this way, and we merely ask the reader to consider how the instinct of sucking in the human infant, or the parental operations of bees, ants, and birds, could be the result either of Natural Selection, or of the intelligently designed actions of individuals of past generations. Even if the last alternative were not inadmissible, the difficulty would be only put back a single step. Whence came the intelligence of these reasoning predecessors of our present bees and babies? 8

The investigations which we have now made into the character of the operations of the animal "soul," render clear the deductions we are justified in drawing concerning its nature, origin, and destiny. The whole weight of analogy proves that in the brute, as in man, the vegetative and sentient principles are identical. This brute "soul," however, is not a spiritual substantial principle, it is not a substantial form intrinsically independent of and separable from its material subject. This doctrine follows immediately from the theses just established. The brute manifests no spiritual activity. It is not endowed with rational intellect nor, consequently, with free-will. In other words, all the mental actions exhibited by it are of the lower or sensuous order, and therefore intrinsically or essentially dependent on a material organism. We are accordingly led to con

8 For an excellent handling of the Evolutionist theory of the Origin of Instinct, cf. Science and Scientists, by Rev. J. Gerard, pp. 100, seq. Cf. also Janet, op. cit. pp. 80-90, 255-259.

clude that the ultimate principle from which these operations proceed is itself intrinsically and essentially dependent on matter. Actio sequitur esse; as a being is, so it acts; but all the mental acts which we are justified in ascribing to brutes are of an organic or sensuous character. Therefore we are bound to infer that the animal "soul" is essentially dependent on the material organism and inseparable from it. It is, consequently, incapable of life apart from the body, and it perishes with the destruction of the latter. On account of this intrinsic dependence on matter, the soul of the brute was spoken of by the Scholastics indifferently as material and corporeal. They did not, however, intend by these terms to imply that the principle of vital activities is a bodily substance of three dimensions. They simply. meant to teach that it depends absolutely on the material subject which it actuates, just as the heat depends on the matter of the burning coal, and the stamped inscription on the wax. They maintained, moreover, that though not spiritual, the vital principle in animals must be of a simple nature, inasmuch as the activity of sentiency which proceeds from it is a simple immanent operation.

The animal soul is thus, in Scholastic language, a substantial form completely immersed in the subject which it animates. Accordingly, it does not require a Divine Creative act to account for its origin in each successive being any more than a Divine Annihilative volition to effect its destruction. It is a result of substantial transformation produced by generation. An existing vital energy is capable by its action of reproducing or evoking from the potentialities of matter a new energy akin to itself. But, as at present new life ever proceeds only from a living agent, so a fortiori in the beginning the primordial act by which animal life was first educed from the potentialities of matter must have been that of a Living Being.

Readings. The ablest English treatment of Animal Intelligence which has yet appeared is Dr. Mivart's recent work, The Origin of Human Reason; cf. also La Bête Comparée à l'Homme, par R. P. De Bonniot, S.J. (Paris.)

INDEX.

ABSTRACT CONCEPTS 238-241, | A PRIORI FORMS, Kantian 109-