There is such a barrier. In the dim but not inadequate vision of the Spiritual World presented in the Word of God, the first thing that strikes the eye is a great gulf fixed. The passage from the Natural World to the Spiritual World is hermetically sealed on the natural side. The door from the inorganic to the organic is shut, no mineral can open it; so the door from the natural to the spiritual is shut, and no man can open it. This world of natural men is staked off from the Spiritual World by barriers which have never yet been crossed from within. No organic change, no modification of environment, no mental energy, no moral effort, no evolution of character, no progress of civilization can endow any single human soul with the attribute of Spiritual Life. The Spiritual World is guarded from the world next in order beneath it by a law of Biogenesis--_except a man be born again ... except a man be born of water and of the Spirit, he cannot enter the Kingdom of God_.
It is not said, in this enunciation of the law, that if the condition be not fulfilled the natural man _will not_ enter the Kingdom of God. The word is _cannot_. For the exclusion of the spiritually inorganic from the Kingdom of the spiritually organic is not arbitrary. Nor is the natural man refused admission on unexplained grounds. His admission is a scientific impossibility. Except a mineral be born "from above"--from the Kingdom just _above_ it--it cannot enter the Kingdom just above it. And except a man be born "from above," by the same law, he cannot enter the Kingdom just above him. There being no passage from one Kingdom to another, whether from inorganic to organic, or from organic to spiritual, the intervention of Life is a scientific necessity if a stone or a plant or an animal or a man is to pass from a lower to a higher sphere. The plant stretches down to the dead world beneath it, touches its minerals and gases with its mystery of Life, and brings them up ennobled and transformed to the living sphere. The breath of God, blowing where it listeth, touches with its mystery of Life the dead souls of men, bears them across the bridgeless gulf between the natural and the spiritual, between the spiritually inorganic and the spiritually organic, endows them with its own high qualities, and develops within them these new and secret faculties, by which those who are born again are said to _see the Kingdom of God_.
What is the evidence for this great gulf fixed at the portals of the Spiritual World? Does Science close this gate, or Reason, or Experience, or Revelation? We reply, all four. The initial statement, it is not to be denied, reaches us from Revelation. But is not this evidence here in court? Or shall it be said that any argument deduced from this is a transparent circle--that after all we simply come back to the unsubstantiality of the _ipse dixit_? Not altogether, for the analogy lends an altogether new authority to the _ipse dixit_. How substantial that argument really is, is seldom realized. We yield the point here much too easily. The right of the Spiritual World to speak of its own phenomena is as secure as the right of the Natural World to speak of itself. What is Science but what the Natural World has said to natural men? What is Revelation but what the Spiritual World has said to Spiritual men? Let us at least ask what Revelation has announced with reference to this Spiritual Law of Biogenesis; afterward we shall inquire whether Science, while indorsing the verdict, may not also have some further vindication of its title to be heard.