The possibilities of reproduction are, of course, very numerous in each case of experience. At present I see before me some books of reference, on the hill at a distance a house partly hidden by trees, and many other things. All these have previously been in my mind, each in various temporal or essential connections with other things. An immense number of images might therefore be reproduced now in my mind. That as a matter of fact I do not become conscious of all of them needs no further explanation. It has been spoken of before when we discussed the limitation, the focalness of consciousness, that is, attention. We have also stated some of the rules determining the selection among these many possibilities. Let us here state these rules more definitely. Whatever tends to bring about strong feeling, also tends to be reproduced. A brilliant success, but also a humiliating defeat, are not easily forgotten. They are always lying in ambush, so to speak, ready for the least opportunity. As in attention, so here even more, pleasant thoughts show this tendency more strongly than unpleasant ones. What is unpleasant is soon repressed. This is illustrated by such facts as the healing power of time, the painting of the future in glowing colors, the unfailing belief that advancing age has in the good old time. A second law governing reproduction may be called the set of the mind. When a railway train enters a large station, there are many paths over which it might pass; but its actual path depends on the position which was given to the switches immediately before the train’s arrival. In a similar manner the path taken by the mind depends on the set established just a few seconds or minutes before by the contents of the mind. If during a conversation in English a French word is unexpectedly pronounced by some one, the other people, though perfectly familiar with the French language, may fail to understand it. The French sounds are unexpected--the track is there, but the switch is not properly set--and consequently the sounds remain ineffective. A certain book seen on my desk calls up associated ideas very different from those which are produced when I see it in the bookstore. The same thought leads to one conclusion in the dark or in a dream, to another conclusion in daylight or in the waking state. Every student is familiar with the difficulty of becoming conscious of the right kind of ideas after having just gone from one recitation room to another. After a few minutes the new set of the mind is established, and the difficulty has disappeared.