From the unicellular animalcule reproducing its kind by fission in the muddy pool to the mammal suckling its little ones in the snow, the deserts and the primeval forests, there is found an incredible variety of means and ingenious inventions of living nature for the sure attainment of her universal end—namely, the propagation, provision, and multiplication of offspring. From the simple processes of conjugation in the microscopic filaments of a mould to the complex mechanisms for pollination by insects in the flowering plants one is struck by the fantastic twistings and modifications of the great mother of living beings, organic nature, to safeguard the continuance of these means.

But it is only where all relevant facts have been collected that theories can be built up and principles abstracted from what has been empirically given. Here, perhaps more than in any field, à priori theories and principles are likely to collapse in the exhaustive evaluation of the individual realities of nature.

A man may be convinced of a principle on philosophical grounds. But if he hopes for an oracular ‘confirmation’ from some aspect of twentieth century science he is usually disillusioned. Few things are more treacherous than the surface of physical nature for him who goes unwarily upon it. Principles either emerge from it more or less immediately (e.g. in our considering Quantity as such), or they do not emerge definitely at all. It is usually fruitless and always foolhardy for the student to venture further than the data of research literally allow. A weapon of apologetics welded from a thin collection of facts tends to snap in a generation, perhaps a decade, and frequently as soon as it is used. The misplaced enthusiasm calling it into existence is false and calls down the derision if not of its own age, then most surely of ages that are to come.