Heat energy of uniform temperature [is] the ultimate fate of all energy. The power of sunlight and coal, electric power, water power, winds and tides do the work of the world, and in the end all unite to hasten the merry molecular dance.

Man cannot influence in this respect the atomic forces of Nature.

The energy available for each individual man is his income, and the philosophy which can teach him to be content with penury should be capable of teaching him also the uses of wealth.

An inexplicable fact is infinitely preferable to an incomprehensible mystery.

Physical science enjoys the distinction of being the most fundamental of the experimental sciences, and its laws are obeyed universally, so far as is known, not merely by inanimate things, but also by living organisms, in their minutest parts, as single individuals, and also as whole communities. It results from this that, however complicated a series of phenomena may be and however many other sciences may enter into its complete presentation, the purely physical aspect, or the application of the known laws of matter and energy, can always be legitimately separated from the other aspects.

Nature is in austere mood, even terrifying, withal majestically beautiful.

The laws expressing the relations between energy and matter are, however, not solely of importance in pure science. They necessarily come first in order ... in the whole record of human experience, and they control, in the last resort, the rise or fall of political systems, the freedom or bondage of nations, the movements of commerce and industry, the origin of wealth and poverty, and the general physical welfare of the race.