This book is an attempt to place the relations of Sex in a new and decisive light. It is an attempt not to collect the greatest possible number of distinguishing characters, or to arrange into a system all the results of scientific measuring and experiment, but to refer to a single principle the whole contrast between man and woman. In this respect the book differs from all other works on the same subject. It does not linger over this or that detail, but presses on to its ultimate goal; it does not heap investigation on investigation, but combines the psychical differences between the sexes into a system; it deals not with women, but with woman. It sets out, indeed, from the most common and obvious facts, but intends to reach a single, concrete principle. This is not “inductive metaphysics”; it is a gradual approach to the heart of psychology.

The investigation is not of details, but of principles; it does not despise the laboratory, although the help of the laboratory, with regard to the deeper problems, is limited as compared with the results of introspective analysis. An artist who wishes to represent the female form can construct a type without actually giving formal proof by a series of measurements. The artist does not despise experimental results; on the contrary, he regards it as a duty to gain experience; but for him the collection of experimental knowledge is merely a starting-point for self-exploration, and in art self-exploration is exploration of the world.

The psychology used in this exposition is purely philosophical, although its characteristic method, justified by the subject, is to set out from the most trivial details of experience. The task of the philosopher differs from that of the artist in one important respect. The one deals in symbols, the other in ideas. Art and philosophy stand to one another as expression and meaning. The artist has breathed in the world to breathe it out again; the philosopher has the world outside him and he has to absorb it.

There is always something pretentious in theory; and the real meaning—which in a work of art is Nature herself and in a philosophical system is a much condensed generalisation, a thesis going to the root of the matter and proving itself—appears to strike against us harshly, almost offensively. Where my exposition is anti-feminine, and that is nearly everywhere, men themselves will receive it with little heartiness or conviction; their sexual egoism makes them prefer to see woman as they would like to have her, as they would like her to be.

I need not say that I am prepared for the answer women will have to the judgment I have passed on their sex. My investigation, indeed, turns against man in the end, and although in a deeper sense than the advocates of women’s rights could anticipate, assigns to man the heaviest and most real blame. But this will help me little and is of such a nature that it cannot in the smallest way rehabilitate me in the minds of women.

The analysis, however, goes further than the assignment of blame; it rises beyond simple and superficial phenomena to heights from which there opens not only a view into the nature of woman and its meaning in the universe, but also the relation to mankind and to the ultimate and most lofty problems. A definite relation to the problem of Culture is attained, and we reach the part to be played by woman in the sphere of ideal aims. There, also, where the problems of Culture and of Mankind coincide, I try not merely to explain but to assign values, for, indeed, in that region explanation and valuation are identical.

To such a wide outlook my investigation was as it were driven, not deliberately steered, from the outset. The inadequacy of all empirical psychological philosophy follows directly from empirical psychology itself. The respect for empirical knowledge will not be injured, but rather will the meaning of such knowledge be deepened, if man recognises in phenomena, and it is from phenomena that he sets out, any elements assuring him that there is something behind phenomena, if he espies the signs that prove the existence of something higher than phenomena, something that supports phenomena. We may be assured of such a first principle, although no living man can reach it. Towards such a principle this book presses and will not flag.

Within the narrow limits to which as yet the problem of woman and of woman’s rights has been confined, there has been no place for the venture to reach so high a goal. None the less the problem is bound intimately with the deepest riddles of existence. It can be solved, practically or theoretically, morally or metaphysically, only in relation to an interpretation of the cosmos.

Comprehension of the universe, or what passes for such, stands in no opposition to knowledge of details; on the other hand all special knowledge acquires a deeper meaning because of it. Comprehension of the universe is self-creative; it cannot arise, although the empirical knowledge of every age expects it, as a synthesis of however great a sum of empirical knowledge.

In this book there lie only the germs of a world-scheme, and these are allied most closely with the conceptions of Plato, Kant and Christianity. I have been compelled for the most part to fashion for myself the scientific, psychological, philosophical, logical, ethical groundwork. I think that at the least I have laid the foundations of many things into which I could not go fully. I call special attention to the defects of this part of my work because I attach more importance to appreciation of what I have tried to say about the deepest and most general problems than to the interest which will certainly be aroused by my special investigation of the problem of woman.

The philosophical reader may take it amiss to find a treatment of the loftiest and ultimate problems coinciding with the investigation of a special problem of no great dignity; I share with him this distaste. I may say, however, that I have treated throughout the contrast between the sexes as the starting-point rather than the goal of my research. The investigation has yielded a harvest rich in its bearing on the fundamental problems of logic and their relations to the axioms of thought, on the theory of Æsthetics, of love, and of the beautiful and the good, and on problems such as individuality and morality and their relations, on the phenomena of genius, the craving for immortality and Hebraism. Naturally these comprehensive interrelations aid the special problem, for, as it is considered from so many points of view, its scope enlarges. And if in this wider sense it be proved that culture can give only the smallest hope for the nature of woman, if the final results are a depreciation, even a negation of womanhood, there will be no attempt in this to destroy what exists, to humble what has a value of its own. Horror of my own deed would overtake me were I here only destructive and had I left only a clean sheet. Perhaps the affirmations in my book are less articulate, but he that has ears to hear will hear them.

The treatise falls into two parts, the first biological-psychological, the second logical-philosophical. It may be objected that I should have done better to make two books, the one treating of purely physical science, the other introspective. It was necessary to be done with biology before turning to psychology. The second part treats of certain psychical problems in a fashion totally different from the method of any contemporary naturalist, and for that reason I think that the removal of the first part of the book would have been at some risk to many readers. Moreover, the first part of the book challenges an attention and criticism from natural science possible in a few places only in the second part, which is chiefly introspective. Because the second part starts from a conception of the universe that is anti-positivistic, many will think it unscientific (although there is given a strong proof against Positivism). For the present I must be content with the conviction that I have rendered its due to Biology, and that I have established an enduring position for non-biological, non-physiological psychology.

My investigation may be objected to as in certain points not being supported by enough proof, but I see little force in such an objection. For in these matters what can “proof” mean? I am not dealing with mathematics or with the theory of cognition (except with the latter in two cases); I am dealing with empirical knowledge, and in that one can do no more than point to what exists; in this region proof means no more than the agreement of new experience with old experience, and it is much the same whether the new phenomena have been produced experimentally by men, or have come straight from the creative hand of nature. Of such latter proofs my book contains many.

Finally, I should like to say that my book, if I may be allowed to judge it, is for the most part not of a quality to be understood and absorbed at the first glance. I point out this myself, to guide and protect the reader.

The less I found myself able in both parts of the book (and especially in the second) to confirm what now passes for knowledge, the more anxious I have been to point out coincidences where I found myself in agreement with what has already been known and said.

I have to thank Professor Dr. Laurenz MÜllner for the great assistance he has given me, and Professor Dr. Friedrich Jodl for the kindly interest he has taken in my work from the beginning. I am specially indebted to the kind friends who have helped me with correction of the proofs.