Many Factors Combine to Allow Life on Earth

As we look at planet Earth and the factors that enabled us to be here, we quickly realize that our planet is very special. Here’s a short list: the long-term existence of a protective and oxygen-rich atmosphere; Earth’s axial tilt, stabilized by a single large moon; the ozone layer and the magnetic field, which jointly protect surface creatures from lethal cosmic radiation; plate tectonics, which regulates the levels of carbon dioxide and keeps the global temperature stable; the fact that...

 Theories Dwindle in Number as Facts Emerge

The intensity and quantity of polemical literature on scientific problems frequently varies inversely as the number of direct observations on which the discussions are based: the number and variety of theories concerning a subject thus often form a coefficient of our ignorance. Beyond the superficial observations, direct and indirect, made by geologists, not extending below about one two-hundredth of the Earth's radius, we have to trust to the deductions of mathematicians for our ideas regard...

 Chemistry Arose from Technologists, Philosophers, and Alc...

Historically [chemistry] arose from a constellation of interests: the empirically based technologies of early metallurgists, brewers, dyers, tanners, calciners and pharmacists; the speculative Greek philosphers' concern whether brute matter was invariant or transformable; the alchemists' real or symbolic attempts to achieve the transmutation of base metals into gold; and the iatrochemists' interst in the chemistry and pathology of animal and human functions. Partly because of the sheer comple...