“Thus this great earth itself, has been but one continued illustration of the great theory and principle of progress. From a beginning, lost in the thick darkness of a past eternity, it has been marching forward in a career as pause-less as the sun in his journeyings through the sky, as clearly demonstrable as the growth of the germ that starts from the buried acorn, and moves on to its full development in the great oak. Science records with unerring certainty the progress of the earth, and of animal life, from the lowest existences in the mollusca and polypi, up to the superlatively complicated, and delicate structure of man, tracing it step by step, until it is finished in the noblest work of God, a human body coupled with an immortal soul!
“And here arises a question which science has not solved, and to which the philosophy, the wisdom, the logic of the past can give no answer. The earth, and the things of the earth, have been moving forward, marching on towards perfectability always. Is this forward movement finished? We have, in looking at the subject in the light of science, a time when there was not on the earth, in the air, or in the water, any living thing. We have an era when animal life was but a span removed from vegetable vitality; we have an era of gigantic vegetable growth; an era of gigantic but rude animal growth, and so on step by step down to the advent of man. The previous combinations of animal life and vegetable life passed away with the era in which they flourished; one class succeeding another, each emerging from, and stepping over the annihilation of its predecessor, till we come down to the present—is there no future progress for this earth as a planet? Is there to be no other era, where man himself, like the sauruses, like the mastodon, shall have passed away, to be succeeded by some nobler animal structure, some loftier intelligence, some more cunning invention of the infinite mind?