in this regard than is the experimental method, the position of which in biological epistemology is now so secure. The real purpose of biometry is the general « quantification » of biology. Its fundamental viewpoint is that without a study of the quantitative relations of biological phenomena in the widest sense it will never be possible to arrive at a full and adequate knowledge of those phenomena. This viewpoint insists that a description which says nothing about the magnitude of the thing described is not complete but, on the contrary, lacks an element of primary importance. It insists, also, that an experiment which takes no account of the «probable error» of the results reached is inadequate and as likely as not to lead to incorrect conclusions. Further, and more broadly, it is certain that not only are quantitative « methods » needed in biology, but also that a far more serious need is for something of the epistemological viewpoint — the mode of thinking — which is characteristic of the exact sciences. What the writer conceives to be the true and basic standpoint of biometry cannot be better expressed than in the following remarks of that master of an exact physical science, Lord Kelvin, in an address on Electrical Units of Measurement[1] .— «I often say that when you can measure what you are speaking about and express it in numbers, you know something about it, but when you can not measure it, when you can not express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts, advanced to the stage of science, whatever the matter may be ».
Having taken this position the next thing in order obviously is to develop mathematical methods especially adapted to the treatment of biological data. Such a step is no more to be criticised than is the demand of the experimentalist that he shall have apparatus adapted to his needs, or of the morphologist that he shall have the latest and best type of microscope for his most detailed and important researches. It is the most obvious right of an investigator that he shall have highly developed and adapted technical
aids whatever his field of work. In accord with this principle
- ↑ « Popular Lect. and Addresses », Vol. I, p. 73.
