The fact is that there is no sort of consciousness whatever, be it sensation, feeling, or idea, which does not directly and of itself tend to discharge into some motor effect. The motor effect need not always be an outward stroke of behavior. It may be only an alteration of the heart-beats or breathing, or a modification in the distribution of blood, such as blushing or turning pale; or else a secretion of tears, or what not. But, in any case, it is there in some shape when any consciousness is there; and a belief as fundamental as any in modern psychology is the belief at last attained that conscious processes of any sort, conscious processes merely as such, _must_ pass over into motion, open or concealed. The least complicated case of this tendency is the case of a mind possessed by only a single idea. If that idea be of an object connected with a native impulse, the impulse will immediately proceed to discharge. If it be the idea of a movement, the movement will occur. Such a case of action from a single idea has been distinguished from more complex cases by the name of 'ideo-motor' action, meaning action without express decision or effort. Most of the habitual actions to which we are trained are of this ideo-motor sort. We perceive, for instance, that the door is open, and we rise and shut it; we perceive some raisins in a dish before us, and extend our hand and carry one of them to our mouth without interrupting the conversation; or, when lying in bed, we suddenly think that we shall be late for breakfast, and instantly we get up with no particular exertion or resolve. All the ingrained procedures by which life is carried on--the manners and customs, dressing and undressing, acts of salutation, etc.--are executed in this semi-automatic way unhesitatingly and efficiently, the very outermost margin of consciousness seeming to be concerned in them, while the focus may be occupied with widely different things. But now turn to a more complicated case. Suppose two thoughts to be in the mind together, of which one, A, taken alone, would discharge itself in a certain action, but of which the other, B, suggests an action of a different sort, or a consequence of the first action calculated to make us shrink. The psychologists now say that the second idea, B, will probably arrest or _inhibit_ the motor effects of the first idea, A. One word, then, about 'inhibition' in general, to make this particular case more clear.