The association--so often found in this connection--of re-birth with a previous return to, and brief sojourn in, the mother's womb, may be due perhaps to some extent to the needs of logical consistency for, as Nicodemus said, a man cannot literally "be born again" unless he has previously "entered the second time into his mother's womb"; but probably it has itself a further and deeper significance. As the result of his researches upon this point, Jung[60] considers that the association in question expresses the necessity of gathering fresh sources of psychic energy from the deepest strata of our mental life in the Unconscious, if the moral or spiritual conversion is to be successful. Starting from the consideration of the products of the collective mind as exemplified in cult and legend rather than from the phantasies of the individual, other investigators, such as Sir J. G. Frazer[61], have come to the conclusion that it is primarily a physical rather than a moral regeneration that is symbolised by the ideas of re-birth. Thus the histories of such divine personages as Attis, Adonis or Osiris, whose death and subsequent return to life are plainly analogous to the phantasy of the return to the mother's womb (burial in the earth) and re-birth from it, have been interpreted as expressions of the desire for rejuvenation on the part of the individual or the race, or again as representations (probably magical in intention) of the periodical decay and revival of vegetation or of the periodical changes of the seasons upon which these depend. This view would seem to be supported by the fact that such a significance (often however associated with that of moral regeneration in Jung's sense) is inherent in many of the mysteries and superstitions of all ages, as in the ideas of the philosopher's stone or the elixir of life, and in the symbolic practices, legends and traditions characteristic of secret societies and of mysticism generally[62]. [Sidenote: The literal interpretation of the womb and birth phantasies] [Sidenote: Sexual significance of the phantasies]