By "intuition" we generally understand a practical, immediate judgment that goes straight to the goal. Tact, wisdom, scent, divination, are synonymous or equivalent expressions. First let us note that intuition does not belong exclusively to this part of our subject, for it is found _in parvo_ throughout; but in commercial invention it is preponderating on account of the necessity of perceiving quickly and surely, and of grasping chances. "Genius for business," someone has said, "consists in making exact hypotheses regarding the fluctuations of values." To characterize the mental state is easy, if it is a matter merely of giving examples; very difficult, if one attempts to discover its mechanism. The physician who in a trice diagnoses a disease, who, on a higher level, groups symptoms in order to deduce a new disease from them, like Duchenne de Boulogne; the politician who knows human nature, the merchant who scents a good venture, etc., furnish examples of intuition. It does not depend on the degree of culture;--not to mention women, whose insight into practical matters is well known, there are ignorant people--peasants, even savages--who, in their limited sphere, are the equals of fine diplomats. But all these facts teach us nothing concerning its psychological nature. Intuition presupposes acquired experience of a special nature that gives the judgment its validity and turns it in a particular direction. Nevertheless, this accumulated knowledge of itself gives no evidence as to the future. Now, every intuition is an anticipation of the future, resulting from only two processes:--inductive or deductive reasoning, e.g., the chemist foreseeing a reaction; imagination, i.e., a representative construction. Which is the chief process here? Evidently the former, because it is not a matter of fancied hypothesis, but of adaptation of former experience to a new case. Intuition resembles logical operations much more than it does imaginative combinations. We may liken it to unconscious reasoning, if we are not afraid of the seeming contradiction of this expression which supposes a logical operation without consciousness of the middle term. Although questionable, it is perhaps to be preferred to other proposed explanations--such as automatism, habit, "instinct," "nervous connections." Carpenter, who as promoter of "unconscious cerebration," deserves to be consulted, likens this state to reflection. In ending, he reprints a letter that John Stuart Mill wrote to him on the subject, in which he says in substance that this capacity is found in persons who have experience and lean toward practical things, but attach little importance to theory.[131]