Science makes no claim to infallibility; it leaves that claim to be made by theologians.

....success in walking is not to let your right foot know what your left foot doeth. Your heart must furnish such music that in keeping time to it your feet will carry you around the globe without knowing it.

Science has done more for the development of western civilization in one hundred years than Christianity did in eighteen hundred years.

Every walk to the woods is a religious rite, every bath in the stream is a saving ordinance. Communion service is at all hours, and the bread and wine are from the heart and marrow of Mother Earth. There are no heretics in Nature's church; all are believers, all are communicants. The beauty of natural religion is that you have it all the time; you do not have to seek it afar off in myths and legends, in catacombs, in garbled texts, in miracles of dead saints or wine-bibbing friars. It is of today; it is now and here; it is everywhere.

[T]he cold warms me—after a different fashion from that of the kitchen stove.

Nature is not benevolent; Nature is just, gives pound for pound, measure for measure, makes no exceptions, never tempers her decrees with mercy, or winks at any infringement of her laws.

There is hardly a man on earth who will take advice unless he is certain that it is positively bad.