1. That such deviations from the normal scheme of an instinct as cannot be referred to conscious deliberation are not provided for by any predisposition in this mechanism.
2. That heredity is only possible under the circumstances of a constant superintendence of the embryonic development by a purposive unconscious activity of growth. It must be admitted, however, that this is influenced in return by the predisposition existing in the germ.
3. That the impressing of the predisposition upon the individual from whom it is inherited can only be effected by long practice, consequently the instinct without auxiliary mechanism [105a] is the originating cause of the auxiliary mechanism.
4. That none of those instinctive actions that are performed rarely, or perhaps once only, in the lifetime of any individual—as, for example, those connected with the propagation and metamorphoses of the lower forms of life, and none of those instinctive omissions of action, neglect of which necessarily entails death—can be conceived as having become engrained into the character through habit; the ganglionic constitution, therefore, that predisposes the animal towards them must have been fashioned purposively.
5. That even the presence of an auxiliary mechanism [105b] does not compel the unconscious to a particular corresponding mode of instinctive action, but only predisposes it. This is shown by the possibility of departure from the normal type of action, so that the unconscious purpose is always stronger than the ganglionic constitution, and takes any opportunity of choosing from several similar possible courses the one that is handiest and most convenient to the constitution of the individual.
We now approach the question that I have reserved for our final one,—Is there, namely, actually such a thing as instinct, [105c] or are all so-called instinctive actions only the results of conscious deliberation?
In support of the second of these two views, it may be alleged that the more limited is the range of the conscious mental activity of any living being, the more fully developed in proportion to its entire mental power is its performance commonly found to be in respect of its own limited and special instinctive department. This holds as good with the lower animals as with men, and is explained by the fact that perfection of proficiency is only partly dependent upon natural capacity, but is in great measure due to practice and cultivation of the original faculty. A philologist, for example, is unskilled in questions of jurisprudence; a natural philosopher or mathematician, in philology; an abstract philosopher, in poetical criticism. Nor has this anything to do with the natural talents of the several persons, but follows as a consequence of their special training. The more special, therefore, is the direction in which the mental activity of any living being is exercised, the more will the whole developing and practising power of the mind be brought to bear upon this one branch, so that it is not surprising if the special power comes ultimately to bear an increased proportion to the total power of the individual, through the contraction of the range within which it is exercised.
Those, however, who apply this to the elucidation of instinct should not forget the words, “in proportion to the entire mental power of the animal in question,” and should bear in mind that the entire mental power becomes less and less continually as we descend the scale of animal life, whereas proficiency in the performance of an instinctive action seems to be much of a muchness in all grades of the animal world. As, therefore, those performances which indisputably proceed from conscious deliberation decrease proportionately with decrease of mental power, while nothing of the kind is observable in the case of instinct—it follows that instinct must involve some other principle than that of conscious intelligence. We see, moreover, that actions which have their source in conscious intelligence are of one and the same kind, whether among the lower animals or with mankind—that is to say, that they are acquired by apprenticeship or instruction and perfected by practice; so that the saying, “Age brings wisdom,” holds good with the brutes as much as with ourselves. Instinctive actions, on the contrary, have a special and distinct character, in that they are performed with no less proficiency by animals that have been reared in solitude than by those that have been instructed by their parents, the first essays of a hitherto unpractised animal being as successful as its later ones. There is a difference in principle here which cannot be mistaken. Again, we know by experience that the feebler and more limited an intelligence is, the more slowly do ideas act upon it, that is to say, the slower and more laborious is its conscious thought. So long as instinct does not come into play, this holds good both in the case of men of different powers of comprehension and with animals; but with instinct all is changed, for it is the speciality of instinct never to hesitate or loiter, but to take action instantly upon perceiving that the stimulating motive has made its appearance. This rapidity in arriving at a resolution is common to the instinctive actions both of the highest and the lowest animals, and indicates an essential difference between instinct and conscious deliberation.
Finally, as regards perfection of the power of execution, a glance will suffice to show the disproportion that exists between this and the grade of intellectual activity on which an animal may be standing. Take, for instance, the caterpillar of the emperor moth (Saturnia pavonia minor). It eats the leaves of the bush upon which it was born; at the utmost has just enough sense to get on to the lower sides of the leaves if it begins to rain, and from time to time changes its skin. This is its whole existence, which certainly does not lead us to expect a display of any, even the most limited, intellectual power. When, however, the time comes for the larva of this moth to become a chrysalis, it spins for itself a double cocoon, fortified with bristles that point outwards, so that it can be opened easily from within, though it is sufficiently impenetrable from without. If this contrivance were the result of conscious reflection, we should have to suppose some such reasoning process as the following to take place in the mind of the caterpillar:—“I am about to become a chrysalis, and, motionless as I must be, shall be exposed to many different kinds of attack. I must therefore weave myself a web. But when I am a moth I shall not be able, as some moths are, to find my way out of it by chemical or mechanical means; therefore I must leave a way open for myself. In order, however, that my enemies may not take advantage of this, I will close it with elastic bristles, which I can easily push asunder from within, but which, upon the principle of the arch, will resist all pressure from without.” Surely this is asking rather too much from a poor caterpillar; yet the whole of the foregoing must be thought out if a correct result is to be arrived at.
This theoretical separation of instinct from conscious intelligence can be easily misrepresented by opponents of my theory, as though a separation in practice also would be necessitated in consequence. This is by no means my intention. On the contrary, I have already insisted at some length that both the two kinds of mental activity may co-exist in all manner of different proportions, so that there may be every degree of combination, from pure instinct to pure deliberation. We shall see, however, in a later chapter, that even in the highest and most abstract activity of human consciousness there are forces at work that are of the highest importance, and are essentially of the same kind as instinct.