apparently different with now one present and again the other, yet forming a single stream of thought.

APPLICATION STEP.-I. Though most psychologists admit that the sensuous material of the outer and the inner order is qualitatively one and the same, it is customary to limit the application of the term perception to the formation of the outer order.

There seems to be no difference in kind, however, on which to base this distinction.

The question is of importance here only when one strives to realize that the whole stream of thought is the action and interaction of sensations the same in kind.

II. Groups of sensations may be now of the inner order, now of the outer, and again mixed, or fused. Of the different groups that are my pencil, for example, one may be at the same time an object, the first member of a train of association; another of the inner order only. The group always has enough sensations that have been in my mind before with the thought, "my pencil," so that I can recognize it each time.

I have as many different "perceptions" of the pencil, then, as I have experiences with it or thoughts about it.

III. Is it not strange that though the secondary members of trains of association, that is, inner thoughts outnumber outer ones overwhelmingly, is it not strange, that, as one thinks over uncritically the last hour it seems to be made up of outer experiences only?

IV. What parts of your world do you habitually make in the terms of taste, smell, touch, resistance, and temperature sensations? In the terms of touch and resistance sensations? In what terms do you think of the inside of the toe of your boot? Of your hat on your head? Of the inside of your pocket?

V. The stream of thought, whatever else it is, seems to be the "epiphenomenon" of the brain condition, and this condition is a resultant blended of all the factors of the present stimuli as modified by the brain's past history, individual, ancestral, and racial.

"All we know of submaximal nerve-irritations, and of the summation of apparently ineffective stimuli, tends to show * * that presumably no changes in the brain are bare of psychological result." (James, "Psychology," Vol. I.)

VI. Do you see that each person makes not only his own rainbow, but in just the same way, his own house, city, world, body, acts, friends, everything?

Dwell on the fact of how individual a matter a mind is. "No man" indeed "knoweth the things of a man save the spirit of the man that is in him."

VII. Can we ever really know another person? Every one about us is for us body and soul, our own creation and construction.

What the incitement is that makes us make different people as we do is a question with which we are not here concerned. The important matter is the comprehension of the fact that we do so make them.

VIII. To the ordinary consciousness there is the mind within and the great world of hard and fast facts outside. And to the psychologist the same is true, except that the psychologist realizes that both are made of the same kind of stuff.

The fact that the outer order is mental should not make it seem any the less real, stable, reliant, orderly. It is never capricious. Since it is as I make it, I might think that, if I wished, I could have a goldpiece in my hand now. I must not think it, however, for no matter how hard I try, my imagination will not make it there as a group of sensations

fitting in with my present outer order. I know as a result of lifelong experience what must be in my physical world, and ordinarily I do not try to make other things there.

IX. By the processes of perception and thought each individual guided by the discoverer builds up and formulates for himself the sciences of physics, astronomy, and all other groups of classified knowledge, out of this world that we make. We can never get outside our minds to find out what the laws that govern us really are-they are as unattainable as Plato's "types laid up in heaven," or as the German "things in themselves," but the sciences that are formulated are the human mind's best guesses at these laws and attempts to classify them.

LESSON III

INFERENCES IN PERCEPTION

PREPARATION STEP.-Some of the inferences that have been assumed in the study of perception should be made explicit.

I. Notice some of the facts that you say you see in connection with the space relations of objects: You say you see that the reading-glass is round; that its lense is curved; its handle cylindrical; that it is large. You "see" that the shears are pointed; that the book has angles; that the table is round. You "see" that the window-seat is two feet wide; that the wall is ten feet distant; that there is space between the houses across the street.

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You see," also, that it rains; that the car moves; that the wind blows; that the bread is done; that the readingglass is made of wood, nickel, and glass; that the table is polished; that fruit looks good; that a friend looks ill.

A little thought will show you that you do not literally see one of these things.

II. You say that you hear a car passing in the street; that you hear your name called; that you hear a person say that it rains.

And here again you do not literally say what you mean.

III. The perspective of scenery in the theatre, the frescoes on the walls of many buildings, deceive us easily,-the distance is inferred from the representation of depth on a flat surface.

IV. I heard some music yesterday. To-day is a holiday, but to-morrow will not be a holiday. Last year at this time there was snow on the ground. I am going to the play Saturday night, and it is now Monday.

These events are all thought of as belonging to a more or less definite time.

V. Go over your own thoughts tracing the trains of association involved in experiences similar to those given above; for example, (1). A group of colors; (2. Thought words) It rains.-(1). A group of sounds; (2. Thought words) It rains.-(1). A group of temperature and pressure sensations; (2. Thought words) It rains.

You would ordinarily say in these cases, first, "I see that it rains;" second, "I hear it rain," and third, "I feel the rain."

PRESENTATION STEP.-I. When one says that he sees that the knife is sharp, what does he really see? Is sharpness a result in mind from the excitation of the optic nerve? Of course not. It is a result of the excitation of the nerves of touch.

In this person's mind a certain group of color sensations, (steel color, lustre, grays) that has been in consciousness before with the touch sensations and the thought word, sharp, is now followed by the same thoughts. Therefore he says that he "sees" that the knife is sharp.

In the same way he may infer by association from a group of colors that the lamp is spherical; that it is two feet distant; that it is in front of him; that it is symmetrical, graceful in shape; that it is one yard from the window. He may infer by associations before established with a group of sound sensations that the can of the lamp is filled; that the shade is of glass; that it is near and in front of him.

Practically all our knowledge of space relations, such as the distance, direction, extent of movement, shape, size, and position of objects is a matter of the association of touch, muscular sensations, colors, and sounds among themselves and with words.

II. I say that I heard my name spoken. What I really heard was a group of sound sensations only. These by previously established association were followed by the thought word, "Cousin."

Thus it is with all language we hear spoken. It is only sounds, absolutely meaningless except as we supply meaning by association. In reading, also, all that we see is color sensations, we must supply all the thoughts.

III. We also associate with color, sound, and touch groups, the names of objects, materials, qualities, quantities, acts, events to a degree incredible to us until we have made a study of these inferences.

IV. How do I know that the music I heard yesterday was sung yesterday and not two years ago?

I know that I heard it yesterday because every hour not only of yesterday, but of my whole life has been known as time only by being filled with events, groups of sensuous elements, my stream of thought. Whatever time has not been filled has not existed for me.

The stream of thought that made the time of yesterday has in many places the thought of Christmas Day, not Saturday. Nor do I go to church on Friday. Two years ago