complexity of the mental processes. Any element in any of the currents may suddenly appear in consciousness or, probably, acquire a dominant influence in the unconscious, and bring with it adjacent elements of its own special wave; and it may be supplanted as suddenly by an element from any other level. So the conscious stream flows on, deriving its elements now from one, now from another, of the tributary unconscious streams below. The thought elements seem to rise into consciousness much as the bubbles of steam rise in boiling water: wherever the heat or activity of the process is sufficiently intense, there they are disengaged.

The cognitive elements within the various strata of this seething mass seem all to be of the same general nature, as being derived through the senses, by present or past impression, and modified by subsequent mental processes of a higher order—an incessant commingling of present and past, from which arise combinations ever new and strange, but of elements never transcending the experience of the individual.

That the unconscious or "subliminal" currents of mind are part of a great sea of intelligence which spreads beyond the limits of the individual, including the unconscious level of all human minds and forming, perhaps, a continuum uniting all the intelligences of the universe, with inclusion of the fundamental and supreme Reality, is a mystic theory which has fascinated many persons but seems without warrant.

Knowing and Feeling. As already stated, the phenomena of consciousness may be distinguished into two types, the physical and the psychic: if we examine the conscious stream from another standpoint

we shall find that it presents two other distinctive qualities, knowing and feeling. To these, from of old, a third quality has been added, that of volition or will; but this quality appears to be, in reality, feeling-feeling as tending toward or, if sufficiently intense, inducing action. The two qualities coexist in every conscious state and also, no doubt, under equivalent forms, in all unconscious states of mind; but, although both qualities are always present, one or the other predominates, and in accordance with such domination we term the state a cognition or a feeling or, at times if we so prefer, a volition.

The feeling function appears to constitute the core or very heart of the individual, the prime mover of the self; the knowing function seems to serve as an instrument for the accomplishment of the other's needs and desires. It is through the function of intellect, acting always under the bias of feeling, that arises all our knowledge and error.

CHAPTER III

THE KNOWING FUNCTION

LET us now consider intellect, in its phases of perception, reasoning, and memory, from the standpoint of proneness to error.

Through our organs of sense we are given knowledge of the so-called external world and of our own bodies. It has long been truly held that our senses cannot deceive us. They simply transmit to the mind, each after its kind, a true report of the impression which they have received, and by the mind this report is truly or falsely interpreted.

Sensation. Our sensations are of many classessuch as the visual, auditory, gustatory, olfactory, and tactile sensations, those derived through the muscles, tendons, joint-surfaces, viscera, etc. Thus we have sensory impressions of color and brightness, tone and pitch, effort or strain, and resistance, hunger, thirst, nausea, and many others. Pure or elementary sensations may be described but have no existence as such in our actual experience, for we know them only as complex combinations. Of the ultimate cause and nature of our sensations we are utterly ignorant. It is doubtful whether we are ever conscious of sensations alone: it is probable that they fuse so rapidly with memories of previous sensations of a similar kind, and

with various more complex processes of the past linked or associated with these, as to present themselves consciously only under the very composite forms known as "percepts."

It is through comparison with previous experience that the mind classifies the data of sensation, and it is in this way that the percept develops. This elaboration into percepts is often a faulty process, and then there arises the "illusion "-an incorrect interpretation of stimuli received through the sense organs. The tendency to illusion is so great that, in point of fact, we need constantly to control the data of one sense by those of another, or by reasoning, to escape this source of error. It happens often that an apparent sensation arises without demonstrable stimulation of any sense organ: this phenomenon we term an hallucination. It may be that in every such case there is really some stimulation of a sense organ and, accordingly, a distinction between these two forms of false sense-perception should not be very finely drawn.

We are so habituated to ourselves and to our environment that we are little aware of the vast amount of illusion amid which we live. Let us recall a few examples from the myriads which are known. The sun appears to move while the earth seems at rest. We sit in a moving train and the trees appear to fly by. The moon seems larger at the horizon than at the zenith. A musical tone is a succession of interrupted sounds but seems a continuous one. The burning point of a stick, rapidly revolved, seems a ring of fire. Jupiter and his six moons to the unaided eye are a single point of light. Let a man be given moderate doses of santonin, and everything that he sees will appear yellow. Such illusions are common to all men. There

are others which are peculiar to individuals. The nearsighted man, as he walks over the grass, sees not the separate blades but merely a diffused green. After amputation of a limb, sensations of numbness, cramp, etc., are felt for a long time as if in the member which has been lost.

The hallucination may involve any one sense, or two or more senses. Thus, we may hear a bell when none has sounded or see the form of a man, hear his voice, and feel his touch, when nothing has really impressed our senses. Many persons in apparent health, especially during fatigue, are subject in greater or less degree to hallucinations. Numerous individuals, reregarded as sane, live in an atmosphere of hallucinations and are frequently in doubt as to whether their sensations are derived from the external world or from within their own minds. Very often, illusions and hallucinations may be recognized as such; but, even by the sane, illusions very often and hallucinations occasionally are accepted as impressions accurately representing reality.

Of the infinite variety of forms which, as we must suppose, the energy of the universe may assume, but an infinitesimal portion comes within the ken of man, through lack of appropriate receptive organs. It has been estimated that the whole number of different sensations possible for us does not exceed forty thousand. The undulations which produce sound become audible only when they have attained a certain frequency per second, and they cease to be audible when a certain rate is exceeded. Similarly with the waves of light. Amid the countless conditions open to our senses at any moment, we take cognizance of but very few and these, even when interpreted with our best