It sometimes happens, owing to special circumstances and conditions of mind, or to peculiar temperaments, that the ideas of things do not remain as mere _thoughts_ in the thinker's mind, but that they become so intense that they are for the moment held to be real, precisely as in a dream.
I do not here speak of abnormal or pathological conditions, or of extraordinary phenomena, but of a normal and common condition. If there is any novelty in the assertion, it is owing to a want of observation and reflection, and to not attempting to trace the real nature of the phenomena in which we take part, and which occur every day. The habitual inaccuracy of observation has led to the use of many proverbs and aphorisms in the interpretation of things which have been transmitted from one generation to another, and are now accepted as indubitable axioms. These are to be found in every branch of knowledge, and we have an instance in the popular and scientific aphorism that in dreams images appear to be real, and that in the waking state they always continue to be mere thoughts and ideas.
This is not the fact, since, putting illusions and hallucinations out of the question, thoughts and ideas sometimes assume the character and nature of real objects, just as they do in dreams. This fact constitutes the link and gradual assimilation of the two states, since in no series of phenomena _natura facit saltum_.
When, for instance, as often happens, we abandon ourselves to a train of thought, and our perception of surrounding objects is weakened by inattention, we become as it were unconscious, and are only intent on the thoughts and ideas which move us. Since no definite object constrains the will to rule and guide these thoughts and ideas, that condition of mind is established which we have shown to be identical in form with the act of dreaming, for in this case also thoughts and ideas have their origin in association alone. In this condition a phenomenon peculiar to dreams may also occur which may be termed the suggestive impulse; a sound or some sudden sensation produces an immediate transformation of the image itself, and a new dream arises in conformity with the nature of the new impression. Every one must, consciously or unconsciously, have experienced such a phenomenon, and this special characteristic of dreams may also take place in the waking condition which I have described. I myself can bear witness to this fact, and will mention one among several instances: I was once reading inattentively, seated at my ease in a lounging chair, and my thoughts took quite another direction, wandering vaguely from one thing to another. All at once some people entered an adjoining room talking together; I heard what they said indistinctly, but the word Florence reached my ears, and I soon imagined myself to be in that city, and going on from one association to another I continued for some time to see again the places, monuments, and people I had known there. Yet I was fully awake, and from time to time I brushed the flies from my face and glanced at the clock on the chimney-piece, since I had to go out at three o'clock.