Hegel would have insisted that his philosophy should be accepted as a whole or not at all. He would have urged that the parts derived their meaning from one another and from the whole. He thought that he had supplied an outline large enough to contain all future knowledge, and a method to which all future philosophies must conform. His metaphysical genius is especially shown in the construction of the categories--a work which was only begun by Kant, and elaborated to the utmost by himself. But is it really true that the part has no meaning when separated from the whole, or that knowledge to be knowledge at all must be universal? Do all abstractions shine only by the reflected light of other abstractions? May they not also find a nearer explanation in their relation to phenomena? If many of them are correlatives they are not all so, and the relations which subsist between them vary from a mere association up to a necessary connexion. Nor is it easy to determine how far the unknown element affects the known, whether, for example, new discoveries may not one day supersede our most elementary notions about nature. To a certain extent all our knowledge is conditional upon what may be known in future ages of the world. We must admit this hypothetical element, which we cannot get rid of by an assumption that we have already discovered the method to which all philosophy must conform. Hegel is right in preferring the concrete to the abstract, in setting actuality before possibility, in excluding from the philosopher's vocabulary the word 'inconceivable.' But he is too well satisfied with his own system ever to consider the effect of what is unknown on the element which is known. To the Hegelian all things are plain and clear, while he who is outside the charmed circle is in the mire of ignorance and 'logical impurity': he who is within is omniscient, or at least has all the elements of knowledge under his hand.