man exists only virtualiter as an acquired facility in calling up certain ideas; actualiter, on the other hand, it also is confined to one idea, and is only conscious of this one at a time. Hence arises a strange contrast between what he knows potentiâ and what he knows actu; that is, between his knowledge and what he thinks at any moment: the former is an immense and always somewhat chaotic mass, the latter is a single distinct thought. The relation resembles that between the innumerable stars of the heavens and the limited field of vision of the telescope; it appears in a striking manner when upon some occasion he wishes to call distinctly to his remembrance some particular circumstance in his knowledge, and time and trouble are required to produce it from that chaos. Rapidity in doing this is a special gift, but is very dependent upon day and hour; therefore memory sometimes refuses us its service, even in things which at another time it has readily at hand. This consideration calls us in our studies to strive more to attain to correct insight than to increase our learning, and to lay it to heart that the quality of knowledge is more important than its quantity. The latter imparts to books only thickness, the former thoroughness and also style; for it is an intensive quantity, while the other is merely extensive. It consists in the distinctness and completeness of the conceptions, together with the purity and accuracy of the knowledge of perception which forms their foundation; therefore the whole of knowledge in all its parts is penetrated by it, and in proportion as it is so is valuable or trifling. With a small quantity, but of good quality, one achieves more than with a very large quantity of bad quality.
The most perfect and satisfactory knowledge is that of perception, but it is limited absolutely to the particular, the individual. The combination of the many and the different in one idea is only possible through the conception, that is, through the omission of the differences; therefore
