A great lecture must have a great theme. One of the supreme tests of a lecturer’s judgment presents itself when he is called upon to choose his subject. Look over the list of subjects on the syllabus of any speaker and the man stands revealed. His previous intellectual training, or lack of it, what he considers important, his general mental attitude, the extent of his information and many other things can be predicated from his selection of topics.

Early in his career the lecturer is obliged to face this question, and his future success hinges very largely on his decision. Not only is the selection determined by his past reading, but it in turn largely determines his future study.

Not long ago a promising young speaker loomed up, but he made a fatal mistake at the very outset. He selected as his special subject a question in which few are interested, except corporation lawyers—the American constitution.

The greatest intellectual achievements of the last fifty years center around the progress of the natural sciences. Those greatest of all problems for the human race, “whence, whither, wherefore,” have found all that we really know of their solution in the discoveries of physics and biology during recent times. What Charles Darwin said about “The Origin of Species” is ten thousand times more important than what some pettifogging lawyer said about “States’ Rights.” The revelations of the cellular composition of animals by Schwan and plants by Schleiden mark greater steps in human progress than any or all of the decisions of the supreme court. Lavoisier, the discoverer of the permanence of matter and the founder of modern chemistry, will be remembered when everybody has forgotten that Judge Marshall and Daniel Webster ever lived. From these and other epoch-making discoveries in the domain of science, modern Socialism gets its point of departure from Utopianism, and without those advances would have been impossible.

Here is a new and glorious world from which the working class has been carefully shut out. Here we find armor that cannot be dented and weapons whose points cannot be turned aside in the struggle of the Proletariat for its own emancipation.

Any lecturer who will acquaint himself with the names of Lamarck, Darwin, Lyell, Lavoisier, Huxley, Haeckel, Virchow, Tyndall, Fiske, Wallace, Romanes, Helmholtz, Leibnitz, Humboldt, Weismann, etc., in science, and Marx, Engels, Lafargue, Labriola, Ferri, Vandervelde, Kautsky, Morgan, Ward, Dietzgen, etc., in sociology, and learn what those names stand for, such a lecturer, other things being equal, has a great and useful field before him.

It was well enough in the middle ages for great conclaves of clericals to discuss sagely what language will be spoken in heaven, and how many angels could dance a saraband on the point of a needle, but the twentieth century is face to face with tremendous problems and the public mind clamors for a solution. It will listen eagerly to the man who knows and has something to say. But it insists that the man who knows no more than it knows itself, shall hold his peace.

This is why the Socialist and the Scientist are the only men who command real audiences—they are the only men with great and vital truths to proclaim.