Thus, in theory, knowledge begins by apprehending existing objects in their specific differences. In the study of nature, for example, we distinguish matters, forces, genera and the like, and stereotype each in its isolation. Thought is here acting in its analytic capacity, where its canon is identity, a simple reference of each attribute to itself. It is under the guidance of the same identity that the process in knowledge is effected from one scientific truth to another. Thus, for example, in mathematics magnitude is the feature which, to the neglect of any other, determines our advance. Hence in geometry we compare one figure with another, so as to bring out their identity. Similarly in other fields of knowledge, such as jurisprudence, the advance is primarily regulated by identity. In it we argue from one specific law or precedent to another: and what is this but to proceed on the principle of identity? But Understanding is as indispensable in practice as it is in theory. Character is an essential in conduct, and a man of character is an understanding man, who in that capacity has definite ends in view and undeviatingly pursues them. The man who will do something great must learn, as Goethe says, to limit himself. The man who, on the contrary, would do everything, really would do nothing, and fails. There is a host of interesting things in the world: Spanish poetry, chemistry, politics, and music are all very interesting, and if any one takes an interest in them we need not find fault. But for a person in a given situation to accomplish anything, he must stick to one definite point, and not dissipate his' forces in many directions. In every calling, too, the great thing is to pursue it with understanding. Thus the judge must stick to the law, and give his verdict in accordance with, it, undeterred by one motive or another, allowing no excuses; and looking neither left nor right. Understanding, too, is always an element in thorough training. The trained-intellect is not satisfied with cloudy and indefinite impressions, but grasps the objects in their fixed character: whereas the uncultivated man wavers unsettled, and it often costs a deal of trouble to come to an understanding with him on the matter under discussion, and to bring him to fix his eye on the definite point in question.