IN order that one person may know what another person is talking about, there must be an agreement in regard to the meaning of the terms employed. Without this there can be no common ground on which those engaged in a discussion as speakers and listeners can stand. For it is obvious that if by a word one of the disputants means one thing and another by the same word means quite another thing, they will both talk of different things, and that hence their statements and arguments will be worse than useless, for they will not only have been of no avail in convincing an adversary or in instructing a pupil, but they will in all probability have been potent agencies in stirring up the bad blood that so often shows itself where, least of all, it ought to appear—in efforts to arrive at the truth.
It is especially necessary that there should be no misunderstanding in regard to one's terminology when we come to discuss those subjects in regard to which our knowledge is not full and precise, and which, consequently, have been studied from different stand-points by different inquirers, and by the light that their own minds have thrown upon them rather than by that of other minds. Suppose, for instance, that a doctor of music should go into the turpentine-regions of North Carolina to give a lecture on "pitch" to the dwellers in the pine-forests, and should talk of the elevation of the voice or of an instrument—is it not quite within the range of probability that some one of the audience would rise in indignation and tell the learned gentleman that he did not know what he was talking about, and that every man, woman, and
- An address delivered at the Lehigh University, on "Founder's Day," October 9, 1884.