As a matter of fact, however, we find a great difference; for the old theories affirm, the modern denies rebirth as a part of the universal process. Modern thought starts from the physical body as the basis of our existence and recognises the reality of no other world except this material universe. What it sees here is a mental consciousness associated with the life of the body, giving in its birth no sign of previous individual existence and leaving in its end no sign of subsequent individual existence. What was before birth is the material energy with its seed of life, or at best an energy of life-force, which persists in the seed transmitted by the parents and gives, by its mysterious infusion of past developments into that trifling vehicle, a particular mental and physical stamp to the new individual mind and body thus strangely created. What remains after death is the same material energy or life-force persisting in the seed transmitted to the children and active for the farther development of the mental and physical life carried with it. Nothing is left of us except what we so transmit to others or what the Energy which shaped the individual by its pre-existent and its surrounding action, by birth and by environment, may take as the result of his life and works into its subsequent action; whatever may help by chance or by physical law to build the mental and vital constituents and environment of other individuals, that alone can have any survival. Behind both the mental and the physical phenomena there is perhaps a universal Life of which we are individualised, evolutionary and phenomenal becomings. This universal Life creates a real world and real beings, but the conscious personality in these beings is not, or at least it need not be, the sign or the shape of consciousness of an eternal nor even of a persistent soul or supraphysical Person: there is nothing in this formula of existence compelling us to believe in a psychic entity that outlasts the death of the body. There is here no reason and little room for the admission of rebirth as a part of the scheme of things.
But what if it were found with the increase of our knowledge, as certain researches and discoveries seem to presage, that the dependence of the mental being or the psychic entity in us on the body is not so complete as we at first naturally conclude it to be from the study of the data of physical existence and the physical universe alone? What if it were found that the human personality survives the death of the body and moves between other planes and this material universe? The prevalent modern idea of a temporary conscious existence would then have to broaden itself and admit a Life that has a wider range than the physical universe and admit too a personal individuality not dependent on the material body. It might have practically to readopt the ancient idea of a subtle form or body inhabited by a psychic entity. A psychic or soul entity, carrying with it the mental consciousness, or, if there be no such original soul, then the evolved and persistent mental individual would continue after death in this subtle persistent form, which must have been either created for it before this birth or by the birth itself or during the life. For either a psychic entity pre-exists in other worlds in a subtle form and comes from there with it to its brief earthly sojourn, or the soul develops here in the material world itself, and with it a psychic body is developed in the course of Nature and persists after death in other worlds or by reincarnation here. These would be the two possible alternatives.
An evolving universal Life may have developed on earth the growing personality that has now become ourselves, before it entered a human body at all; the soul in us may have evolved in lower life-shapes before man was created. In that case, our personality has previously inhabited animal forms, and the subtle body would be a plastic formation carried from birth to birth but adapting itself to whatever physical shape the soul inhabits. Or the evolving Life may be able to build a personality capable of survival, but only in the human form when that is created. This would happen by the force of a sudden growth of mental consciousness, and at the same time a sheath of subtle mind substance might develop and help to individualise this mental consciousness and would then function as an inner body, just as the gross physical form by its organisation at once individualises and houses the animal mind and life. On the former supposition, we must admit that the animal too survives the dissolution of the physical body and has some kind of soul formation which after death occupies other animal forms on earth and finally a human body. For there is little likelihood that the animal soul passes beyond earth and enters other planes of life than the physical and constantly returns here until it is ready for the human incarnation; the animal’s conscious individualisation does not seem sufficient to bear such a transfer or to adapt itself to an other-worldly existence. On the second supposition, the power thus to survive the death of the physical body in other states of existence would only arrive with the human stage of the evolution. If, indeed, the soul is not such a constructed personality evolved by Life, but a persistent unevolving reality with a terrestrial life and body as its necessary field, the theory of rebirth in the sense of Pythagorean transmigration would have to be admitted. But if it is a persistent evolving entity capable of passing beyond the terrestrial stage, then the Indian idea of a passage to other worlds and a return to terrestrial birth would become possible and highly probable. But it would not be inevitable; for it might be supposed that the human personality, once capable of attaining to other planes, need not return from them: it would naturally, in the absence of some greater compelling reason, pursue its existence upon the higher plane to which it had arisen; it would have finished with the terrestrial life-evolution. Only if faced with actual evidence of a return to earth, would a larger supposition be compulsory and the admission of a repeated rebirth in human forms become inevitable.
But even then the developing vitalistic theory need not spiritualise itself, need not admit the real existence of a soul or its immortality or eternity. It might regard the personality still as a phenomenal creation of the universal Life by the interaction of life consciousness and physical form and force, but with a wider, more variable and subtler action of both upon each other and another history than it had at first seen to be possible. It might even arrive at a sort of vitalistic Buddhism, admitting Karma, but admitting it only as the action of a universal Life-force; it would admit as one of its results the continuity of the stream of personality in rebirth by mental association, but might deny any real self for the individual or any eternal being other than this ever-active vital Becoming. On the other hand, it might, obeying a turn of thought which is now beginning to gain a little in strength, admit a universal Self or cosmic Spirit as the primal reality and Life as its power or agent and so arrive at a form of spiritualised vital Monism. In this theory too a law of rebirth would be possible but not inevitable; it might be a phenomenal fact, an actual law of life, but it would not be a logical result of the theory of being and its inevitable consequence.