I cannot conceive of a god who rewards and punishes his creatures or has a will of the kind we experience in ourselves. Neither can I nor would I want to conceive of an individual that survives his physical death; let feeble souls, from fear or absurd egotism, cherish such thoughts. I am satisfied with the mystery of the eternity of life and a glimpse of the marvelous structure of the existing world, together with the devoted striving to comprehend a portion, be it ever so tiny. In theory, there is no difference between theory and practice. But, in practice, there is.