From some of the criticisms on the First Edition of this work I fear that the distinction I endeavoured to draw between the use of the term “polarity” in the inorganic and in the spiritual worlds has not been made sufficiently clear. I stated in the Introduction “That while the principle of polarity pervades both worlds, I am far from assuming that the laws under which it acts are identical; and that virtue and vice, pain and pleasure, are products of the same mathematical laws as regulate the attractions and repulsions of molecules and atoms.” But this warning has been apparently overlooked by some readers who have assumed that instead of analogy I meant identity, and that it was a mistake to use the same word “polarity” for phenomena so essentially distinct as those of the material and the spiritual worlds.

Thus my “guide, philosopher, and friend,” Professor Huxley, for whose authority I have the highest respect, observed in a recent article, that he had long ago acquired a habit, if he came across the word polarity applied to anything but magnetism and electricity, of throwing down the book and reading no farther. I must confess that I felt a little disconcerted when I read this passage; but I was soon consoled, for, in a month or two afterwards, I came across another passage in the same Review which said, “However revolting may be the accumulation of misery at the negative pole of Society, in contrast with that of monstrous wealth at the positive pole, this state of things must abide and grow continuously worse, as long as Istar (the dual Goddess of the Babylonians) holds her way unchecked.”

Surely, I thought, here is a case in which the Professor must have thrown down the Review when he came to these words: but when I came to the end, I found that it was not the Review, but the pen, which must have been thrown down, for the article is signed “T. Huxley.” Can there be a more conclusive proof that there are a vast variety of facts outside of magnetism and electricity, connected by an underlying idea, which inevitably suggests analogy to them, and which can be most conveniently expressed by the word “polarity”? Words after all are only coins to facilitate the interchange of ideas, and the best word is that which serves the purpose most clearly and concisely. Thus instead of using a waggon load of copper, or the verbiage of a conveyancer’s deed, to express the ideas comprised in such words as “theism,” “pantheism,” or “agnosticism,” we coin them for general use, as Huxley did the word “agnosticism,” in order to convey our meaning.

Polarity is such a word. It sums up what Emerson says in his Essay on Compensation: “Polarity, or action and reaction, we meet in every part of Nature; in darkness and light; in the ebb and flow of waters; in male and female; in the inspiration and expiration of plants and animals; in the undulations of fluids and of sound; in the centripetal and centrifugal gravity; in electricity, galvanism, and chemical affinity. Superinduce Magnetism at one end of a needle, the opposite Magnetism takes place at the other end. If the South attracts, the North repels. An inevitable dualism besets nature, so that each thing is a half, and suggests another to make it whole: as spirit, matter; man, woman; odd, even; subjective, objective; in, out; upper, under; motion, rest; yea, nay.”

These, by whatever name we like to call them, are facts and not fancies, and facts which enter largely into all questions, whether of science, philosophy, religion, or practical policy. Every one who wishes to keep at all abreast with modern culture, ought to have some general knowledge of the ideas and principles which underlie them and which are embraced in the comprehensive word “polarity.” My object in this book has been to assist the reader, who is not a specialist, in arriving at some general understanding of the subjects treated of, and I may hope, in awakening such an interest in them as may induce him to prosecute further researches. If I succeed in this, my object will have been attained.