All over the world there lingers on the memory of a giant tree, the primal tree, rising up from the centre of the Earth to the heavens and ordering the universe around it. It united the three worlds: its roots plunged down into subterranean abysses, Its loftiest branches touched the empyrean. Thanks to the Tree, it became possible to breathe the air; to all the creatures that then appeared on Earth it dispensed its fruit, ripened by the sun and nourished by the water which it drew from the soil. From the sky it attracted the lightning from which man made fire and, beckoning skyward, where clouds gathered around its fall. The Tree was the source of all life, and of all regeneration. Small wonder then that tree-worship was so prevalent in ancient times.

Astronomers and physicists, dealing habitually with objects and quantities far beyond the reach of the senses, even with the aid of the most powerful aids that ingenuity has been able to devise, tend almost inevitably to fall into the ways of thinking of men dealing with objects and quantities that do not exist at all, e.g., theologians and metaphysicians. Thus their speculations tend almost inevitably to depart from the field of true science, which is that of precise observation, and to become mere soaring in the empyrean. The process works backward, too. That is to say, their reports of what they pretend actually to see are often very unreliable. It is thus no wonder that, of all men of science, they are the most given to flirting with theology. Nor is it remarkable that, in the popular belief, most astronomers end by losing their minds.

The flight of most members of a profession to the high empyrean, where they can work peacefully on purely scientific problems, isolated from the turmoil of real life, was perhaps quite appropriate at an earlier stage of science; but in today's world it is a luxury we cannot afford.