take this as a sample of the nature of a conscious situation which is effective in guidance. We have seen the nature of the elements (sensory data, including as essential those supplied by the behaviour itself, with a pleasurable or painful tone) which enter into such a situation; we have seen that they owe their primary origin to direct presentation, but that they may be subsequently introduced indirectly in re-presentative form; we have seen that the situation as a whole results from the coalescence of the data. There only remains the question how the felt situation takes effect on behaviour. And to this question, unfortunately, we can give but a meagre and incomplete reply. All we can say is, that connections. seem to be in some way established between the centres of conscious control and the centres of congenital response ; and that through these channels the responsive behaviour may be either checked or augmented (as a whole or in part), according to the tone, disagreeable or pleasant, that suffuses the situation. How this is effected we do not fully know.

III. LATER PHASES IN MENTAL DEVELOPMENT

Some surprise may be felt that in our brief discussion of the early stages of mental development nothing has been said of percepts and concepts, nothing of abstraction or generalization. The omission is not only due to a desire to avoid the subtle technicalities of psychological nomenclature. It is partly due to the wish not to forejudge a difficult question of interpretation. Spirited passages of arms from time to time take place between psychologists in opposing camps, as to whether animals are or are not capable of forming abstract and general ideas; and untrained camp followers hang on the skirts of the fray, making a good deal of noise with blankcartridge. The question at issue turns partly on the definitions of technical terms; partly, when there is agreement on this point, on the interpretation to be put on certain modes of behaviour. Nothing seems at first sight much easier than to say what we mean by an abstract idea or by a general idea.

We are thinking about colour, which is both abstract and general-abstract, because in itself it is a special quality of visible objects floated off, so to speak, from other qualities, such as hardness and weight, shape and size; general, because it includes many different colours in one group. Looking up at the bookshelves, we see a volume with a red back. We neglect the shape, the contents, the lettering; it is the colour with which we are immediately concerned, which forms an important feature in the present thought-situation; and this is, in virtue of that situation, abstracted from the rest. But a chick a few days old may have acquired experience of several kinds of caterpillars much alike in shape and size; of which, one kind is ringed with orange and black. And while the others. are eagerly seized, caterpillars of this kind are left untouched. It is not the size or the shape which is an effective element in the situation; it is the peculiar coloration of the cinnabar caterpillars. Now, does the effectiveness of this quality in the stimulus justify the inference that the chick forms an abstract idea of colour? That clearly depends on our definition of abstract idea, and on our inferences concerning the nature of the chick's mind.

A dog lies dozing upon the mat, and hears a step in the porch without. His behaviour at once shows that this enters into the conscious situation. There is, moreover, a marked difference according as the step has the familiar fall of the master's tread, the well-known shuffle of the irrepressible butcher's lad, or an unfamiliar sound. These several situations are, without question, nicely distinguished. Let us suppose the situation of the moment is introduced by a strange footfall. It seems to suggest man; but this cannot be any particular man, since he is as yet invisible and is a stranger. Does the dog, then, frame a general idea of man? Does the chamois do so when, bounding across the snow field, he stops suddenly on scenting the distant footprints of a mountaineer? Do you do so when you hear the bleating of an invisible lamb in the meadow behind yonder wall? Here, again, the answers we give to these questions depend partly on the exact meaning

of the term "general idea; " partly on our interpretation of what passes through the mind of the being concerned. We have sought, so far, rather to avoid than to answer these questions. We seem to be on safe ground so long as we content ourselves with saying that the orange and black of the cinnabar caterpillar, the strange footfall, or the trail of the mountaineer, enter as effective elements into the immediate conscious situation.

But when we pass to the higher phases of mental development we can no longer wholly ignore such questions. When we are dealing with intellectual human beings, there can be no doubt that they at least are capable of framing, with definite intention, and of set purpose, both general and abstract conceptions. And how do they reach these conceptions? By reviewing a number of past situations, analyzing them, intentionally disentangling and isolating for the purposes of their thought certain elements which they contain, and classifying these abstracts under genera and species that is to say, into broader and narrower groups. The primary and proximate object of this process is to reach a scheme of thought by which the scheme of nature, as given in experience, can be explained. And, no doubt, underlying this primary object is the purpose of guiding future behaviour in accordance with the rational scheme which is thus attained. Man is sometimes described as par excellence the being who looks before and after. All his greatest achievements are due to his powers of reflection and foresight.

What share the symbolism of speech takes in the process briefly indicated in the last paragraph is the subject of much discussion. Without going so far as to urge that the very beginnings of reflective thought are inexplicable without its aid, it may be accepted as obviously true that words are a great assistance. They may be regarded as intellectual pegs upon which we hang the results of abstraction and generalization. It may be said that we often think in pictures or images, and not in words; but the more abstract and general our thought, the more it is dependent on the symbolic elements.

We may say, then, that the higher phases of mental development are characterized by the fact that the situations contain the products of reflective thought, presumably absent in the earlier stages; they are further characterized by a new purpose or end of consciousness, namely, to explain the situations hitherto merely accepted as they are given in presentation or re-presentation; they require deliberate attention to the relationships which hold good among the several elements of successive situations; and they involve, so far as behaviour is concerned, the intentional application of an ideal scheme with the object of rational guidance. We shall follow Dr. Stout in terming this later stage of mental development the ideational stage; and in speaking of the simpler situations considered in the preceding section as belonging to the perceptual stage.

It should be observed that we are not attempting to determine just where, in the scale of organic existence, the line between the perceptual and the ideational stages of mental development is to be drawn. We are certainly very far from asserting that the one does not give rise to the other in the course of an evolution which is orderly and progressive. We are merely contrasting the rational guidance of effective consciousness at its best with the earlier embryonic condition out of which it has arisen by natural genesis. In doing this we have been forced to make some reference to the difficulties of technical nomenclature. And some further reference is necessary lest our point of view be misunderstood.

We shall regard these abstract and general ideas as the products of an intentional purpose directed to the special end of isolating the one and of classifying the other; we shall reserve the term rational for the conduct which is guided in accordance with an ideal scheme or deliberate plan of action; while for behaviour to the guidance of which no such reflection and deliberation seems to have contributed we shall reserve the term intelligent. If, for example, the rejection of a cinnabar caterpillar by the chick is the direct result of experience through the re-presentation in the new situation.

of certain elements introduced during the development of a like situation, we shall call it an intelligent act. But if we have grounds for supposing that the situation is reflectively considered by the chick in relation to an ideal and more or less definitely conceived plan of action which is (perhaps dimly) taking form in its mind, we shall regard it as so far rational. And so, too, in other cases of animal behaviour. Now, with regard to the control through which consciousness is effective in the guidance of behaviour, it is necessary, in view of these considerations, to distinguish its intelligent from its rational exercise. And this is of importance since we generally speak of control in the latter sense in reference to human conduct. Intelligent control (on the perceptual plane) is due to the direct operation of the results of experience without the intervention of any generalized conception or ideal. In rational control (on the ideational plane), such conceptions and ideals exert a controlling influence. If, to prevent a boy sucking his thumb we administer bitter aloes, we trust to intelligent control through the immediate effects of experience; but if he be induced to give up the habit because it is babyish, he so far exercises rational control. What we call self-control is of this type. Only one more distinction need be drawn. Intelligent behaviour, founded on direct association gained through previous experience, we shall attribute to impulse; but for rational conduct, the outcome of reflection and deliberation, we seek to ascertain the motive. In human affairs our motives are referred to certain categories each of which presupposes an ideal scheme, prudential, æsthetic, ethical, or other. To act from motive and not from impulse is to act deliberately, because we judge the action to be expedient, seemly, or right, as the case may be. If, then, we contrast the lower perceptual stages of mental evolution with the higher ideational phases, the former includes behaviour due to impulse; but from it conduct due to motive is excluded.