"It should be ever borne in mind that Patanjali had no need to assert or enforce the doctrine of reincarnation. That is assumed all through the Aphorisms. That it could be doubted, or need any restatement, never occurred to him, and by us it is alluded to, not because we have the smallest doubt of its truth, but only because we see about us those who never heard of such a doctrine, who, educated under the frightful dogmas of Christian priestcraft, imagine that upon quitting this life they will enjoy heaven or be damned eternally, and who not once pause to ask where was their soul before it came into the present body. Without Reincarnation Patanjali's Aphorisms are worthless. Take No. 18, Book III, which declares that the ascetic can know what were his previous incarnations with all their circumstances; or No. 13, Book II, that while there is a root of works there is fructification in rank and years and experience. Both of these infer reincarnation. In Aphorism 8, Book IV, reincarnation is a necessity. The manifestation, in any incarnation, of the effects of mental deposits made in previous lives, is declared to ensue upon the obtaining of just the kind of bodily and mental frame, constitution and environment as will bring them out. Where were these deposits received if not in preceding lives on earth — or even if on other planets, it is still reincarnation. And so on all through the Aphorisms this law is tacitly admitted. (Preface)"