Otto Weininger

“ It has not been recognised that in pure, as opposed to applied, science it is the type that must be studied. And so those who are concerned with the type must turn their backs on the methods and conclusions of current morphology and physiology. The real measurements and investigations of details have yet to be made. Those that now exist are inapplicable to true science. ”

“ Living beings cannot be described bluntly as of one sex or the other. The real world from the point of view of sex may be regarded as swaying between two points, no actual individual being at either point, but somewhere between the two. The task of science is to define the position of any individual between these two points. ”

“ The course of statistical science, which marks off our industrial age from earlier times, although perhaps on account of its distant relation to mathematics it has been regarded as specially scientific, has in reality hindered the progress of knowledge. ”

“ The more obvious this uncertainty in the theory of sexual intermediate forms may be, the more is it to be deplored in the interests of true science. Anatomists and anthropologists of the ordinary type have by no means striven against the scientific representation of the sexual types, but as for the most part they regarded measurements as the best indications, they were overwhelmed with the number of exceptions, and thus, so far, measurement has brought only vague and indefinite results. ”

“ Different kinds of animals and plants may be distinguished by the extent to which the characters of one sex are rudimentary in the other. The most extreme case of sexual differentiation, the sharpest gonochorism, occurs in sexual dimorphism, that is to say, in that condition of affairs in which (as for instance in some water-fleas) the males and females of the same species differ as much or even more from each other as the members of different species, or genera. ”

“ In the case of a human embryo of less than five weeks, for instance, the sex to which it would afterwards belong cannot be recognised. In the fifth week of fœtal life processes begin which, by the end of the fifth month of pregnancy, have turned the genital rudiments, at first alike in the sexes, into one sex and have determined the sex of the whole organism. ”

“ Amongst human beings the state of the case is as follows: There exist all sorts of intermediate conditions between male and female—sexual transitional forms. In physical inquiries an "ideal gas" is assumed, that is to say, a gas, the behaviour of which follows the law of Boyle-Guy-Lussac exactly, although, in fact, no such gas exists, and laws are deduced from this so that the deviations from the ideal laws may be established in the case of actually existing gases. ”

“ In the same fashion we may suppose the existence of an ideal man, M, and of an ideal woman, W, as sexual types although these types do not actually exist. Such types not only can be constructed, but must be constructed. ”

“ Thus, in the case of human beings, in which our interest is greatest, to take an example, it will be found that the most womanly woman has a growth of colourless hair, known as "lanugo" in the position of the male beard; and in the most manly man there are developed under the skin of the breast masses of glandular tissue connected with the nipples. ”

“ The absolute conditions at the two extremes are not metaphysical abstractions above or outside the world of experience, but their construction is necessary as a philosophical and practical mode of describing the actual world. ”