_Instances in proof of this Position._--In support of this position he refers to certain cases as instances of unconscious perception; as when, for example, a clock strikes within a few feet of us, while we are busily engaged, and we do not notice it, or know that it has struck, yet if questioned afterward, are conscious of an impression that we have heard it; as when also while reading aloud to another person, some thought arrests our attention, and yet by a sort of mechanical process, we continue the reading, our mind, meanwhile, wholly occupied with another subject, until presently we are startled to find that we have not the remotest conception of what we have just been reading; yet we read every word correctly, and must, it would seem, have perceived every word and letter. He refers also to the case of the short-hand writer to the House of Lords in England, who, on a certain occasion, while engaged in taking the depositions of witnesses in an important case, after many hours of continued exertion and fatigue, fell, for a few moments, into a state of entire unconsciousness, yet kept on writing down, and that with perfect accuracy, the depositions of the witness. Of the last few lines, when he came to read them, he had no recollection whatever, yet they were written as legibly and accurately as the rest. From these and similar cases it is inferred that there may be mental activity of which we have at the time no consciousness. _The Evidence examined._--With regard to the cases now cited, it seems to me that they do not fully establish the point in question. For in the first place, it may be doubted whether they really involve any mental activity--whether they are properly mental acts, and not merely mechanical or automatic. It is well known that many processes which ordinarily require more or less attention may, when they have become perfectly familiar, be carried on for a time almost without thought. The senses, so far as they are required to act at all, seem in such cases to act mechanically or automatically, somewhat as a wheel when once set in motion continues for a time to revolve by its own momentum, after the propelling force is withdrawn. The mental activity exerted in such cases, if there be any, is so very slight as to escape attention, and we are unconscious of it simply because there was little or nothing to be conscious of. We have an illustration of this in the act of walking, while busily engaged in conversation with a friend, or in our own meditations. We are not conscious of any mental act preceding or directing each step and movement of the limbs, but having at the outset decided what direction to take, the mind gives itself to other matters, while the process of walking goes on by a sort of mechanical impulse, until presently something occurs to arrest our attention and direct it to the physical movement in which we are engaged. The muscular contractions tend to follow each other in