In any discussion that aims at scientific precision it is necessary to give to the principal terms used a far more definite meaning than is given to them when they are used ordinarily; for most words when used ordinarily have several meanings, but when used technically they must have only one. Any term, then, when used technically will of necessity specifically exclude a number of ideas—and it may be very important ones—which are frequently attached to it when it is used in conversation or general literature. This observation, as the reader will readily perceive, has a special application to our use of the term _great man_. The greatness of the great man, regarded as an agent of progress, is a quality, as has been said, which is to be measured by its overt results; and its overt results consist of, and are brought about by, not what he does in his own person, but what he makes others do. It is needless to insist {252} upon this truth again, as it has been explained at great length already, and it is impossible that any reader can misunderstand it. What it is necessary for us here to explain and insist upon is its converse—namely, that if the essence of technical greatness is so to influence the actions or thoughts of other men that the productivity of human labour is increased or the scope of human thought enlarged, no man is technically great who is not in this way influential. When we come to reflect closely on this definition, some of the results will strike us as not a little curious; for if we exclude from the class of great men and relegate to the class of ordinary men all those whose greatness begins and ends with themselves, and does not tend to communicate itself to any one beside themselves, so as to make others think or act more efficiently than they would unaided, ordinary men, or the many, in our present technical sense of the words, will include a number of men of the most brilliant capacities and accomplishments.