At the basis of every science, as we have seen, there are certain ideas which cannot be conveyed to other minds by the use of the corresponding technical terms. These basal concepts must be built up in the learner’s mind by skilful teaching, sometimes by the very process by which the race acquired or discovered them. It may require a trip to the field, to the museum, or to the mine; or an experiment in the laboratory may be necessary. Perhaps a development lesson is needed to enable the pupil to grasp the idea clearly and fully. It is very certain that if the idea is hazy and ill-defined, the subsequent thinking will be loose, obscure, and unsatisfactory. The glib use of technical terms may often hide from the teacher the defects of the pupil’s thinking, and it may require an examination to reveal the points wherein the teacher has failed. Questions which require a pupil to look at his knowledge from a new point of view are helpful; an examination abounding in such questions may be an intellectual blessing to both teacher and pupil. The examiner should, of course, avoid puzzling catch-questions, for these are calculated to embarrass the pupil and confuse his thinking.
A clear thinker can always make his ideas intelligible to those who have acquired the basal concepts of the things, principles, and laws with which he deals. Lecturers on popular science avoid the abstruse questions of advanced science and the technical terms which do not convey a definite meaning to the average hearer. They select topics which can be discussed in the language of common life, and often state the results of scientific research without leading the audience through the successive steps by which these results are obtained. The popular lecture requires special gifts that are not in the possession of every scientist. Huxley was one of the most gifted men of the century; yet he says of himself,—
“I have not been one of those fortunate persons who are able to regard a popular lecture as a mere _hors d’œuvre_ unworthy of being ranked among the serious efforts of a philosopher, and who keep their fame as scientific hierophants unsullied by attempts—at least of the successful sort—to be understanded by the people. On the contrary, I have found that the task of putting the truths learned in the field, the laboratory, and the museum into language which, without bating a jot of scientific accuracy, shall be generally intelligible, taxed such scientific and literary faculty as I possessed to the uttermost; indeed, my experience has furnished me with no better corrective of the tendency to scholastic pedantry, which besets all those who are absorbed in pursuits remote from the common ways of men, and become habituated to think and speak in the technical dialect of their own little world, as if there were no other.”