Ego, or "I," is a something immaterial, ruling the material body which it inhabits. And so the Reincarnationists claim that this demand upon them for proof of the existence of the soul is not a fair one, because such discussion belongs to the more general field of thought; that they are justified in starting with the idea that the soul does exist, as an axiomic truth; and that their real task is to establish, not that the soul exists, but that it reincarnates after the death of the body. As Figuier says, "The difficulty is not to prove that there is a spiritual principle in us that resists death, for to question the existence of this principle we must doubt thought. The true problem is to ascertain if the spiritual and immortal principle within us is going to live again after death, in ourselves or somebody else. The question is, Will the immortal soul be born again in the same individual, physically transformed--into the same person?" As to the other objection, that the Reincarnationists have not proven the nature of the soul, to which many of the advocates of the doctrine feel it necessary to reply at great length and with much subtle reasoning, we feel that the objection is not well taken. So far as Reincarnation is concerned, if it be taken as an axiom that the soul really exists, that is sufficient as a beginning for the argument in favor of the doctrine, and the proof or disproof of any special theory regarding the nature of the soul is outside of the main question, so we shall not consider it here. It is possible to think of the soul as a reincarnating entity, whether it be a monad, duad, triad, or septenary being.