From my friend Jerry Coyne’s Why Evolution Is True:
From someone we should all read more of: Robert G. Ingersoll, the Great Agnostic.
This is from The Gods and Other Lectures (1876), and is the best mission statement I know for atheists, both old a new:
Notwithstanding the fact that infidels in all ages have battled for the rights of man, and have at all times been the fearless advocates of liberty and justice, we are constantly charged by the church with tearing down without building again. The church should by this time know that it is utterly impossible to rob men of their opinions. The history of religious persecution fully establishes the fact that the mind necessarily resists and defies every attempt to control it by violence. The mind necessarily clings to old ideas until prepared for the new. The moment we comprehend the truth, all erroneous ideas are of necessity cast aside.
A surgeon once called upon a poor cripple and kindly offered to render him any assistance in his power. The surgeon began to discourse very learnedly upon the nature and origin of disease; of the curative properties of certain medicines; of the advantages of exercise, air and light, and of the various ways in which health and strength could be restored. These remarks ware so full of good sense, and discovered so much profound thought and accurate knowledge, that the cripple, becoming thoroughly alarmed, cried out, “Do not, I pray you, take away my crutches. They are my only support, and without them I should be miserable indeed!” “I am not going,” said the surgeon, “to take away your crutches. I am going to cure you, and then you will throw the crutches away yourself.”
For the vagaries of the clouds the infidels propose to substitute the realities of earth; for superstition, the splendid demonstrations and achievements of science; and for theological tyranny, the chainless liberty of thought.