Theories of Cosmic Evolution

The framing of theories is an occupation in which men like to indulge. To imagine how things may have come about is probably the nearest approach to a creative act to which we finite beings will ever attain; and the field of astronomy has been an especially tempting one in which to try our creative powers. We like to do things on a large scale; and it is quite as easy to construct, in imagination, a planet or a solar system as something less pretentious. From the first men have been explaining how the cosmos came to be; naturally these imaginings have reflected strongly the philosophy of the times and places and peoples that gave them birth. We have had theories spiritual, theories fanciful, and theories frivolous. Men have told us how the civil engineers on neighbouring planets run their lines and dig their Culebra cuts; and long before this age of engineering they have explained how the starry sky was peopled with divinities and heroes