"Supposing that man, in some form, is permitted to remain on the earth for a long series of years, we merely lengthen out the period, but we cannot escape the final catastrophe. The earth will gradually lose its energy of relation, as well as that of revolution round the sun. The sun himself will wax dim and become useless as a source of energy, until at last the favorable conditions of the present solar system will have quite disappeared. "But what happens to our system will happen likewise to the whole visible universe, which will, if finite, become a lifeless mass, if indeed it be not doomed to utter dissolution. In fine, it will become old and effete, no less truly than the individual. It is a glorious garment, this visible universe, but not an immortal one. We must look elsewhere if we are to be clothed with immortality as with a garment."--_The Unseen Universe._ "This is Life Eternal--that they might know Thee, the True God, and Jesus Christ whom Thou hast sent."--_Jesus Christ._ "Perfect correspondence would be perfect life. Were there no changes in the environment but such as the organism had adapted changes to meet, and were it never to fail in the efficiency with which it met them, there would be eternal existence and eternal knowledge."--_Herbert Spencer._ One of the most startling achievements of recent science is a definition of Eternal Life. To the religious mind this is a contribution of immense moment. For eighteen hundred years only one definition of Life Eternal was before the world. Now there are two. Through all these centuries revealed religion had this doctrine to itself. Ethics had a voice, as well as Christianity, on the question of the _summum bonum_; Philosophy ventured to speculate on the Being of a God. But no source outside Christianity contributed anything to the doctrine of Eternal Life. Apart from Revelation, this great truth was unguaranteed. It was the one thing in the Christian system that most needed verification from without, yet none was forthcoming. And never has any further light been thrown upon the question why in its very nature the Christian Life should be Eternal. Christianity itself even upon this point has been obscure. Its decision upon the bare fact is authoritative and specific. But as to what there is in the Spiritual Life necessarily endowing it with the element of Eternity, the maturest theology is all but silent.