Question: How are the souls of men brought forth? Does this occur by seminal procreation or by transmission and ignition as one candle transmits light to another candle? Or does God create the soul whenever man by procreation comes into existence?
Answer: First, the soul is a spiritual entity, and thus is not physical in any sense. Therefore the soul cannot be brought forth by means of corporal and seminal procreation, for that which is causal cannot bring forth something which is toto genere, that is, of a nobler generation than the cause itself. If one maintains that the soul does not proceed from the body, but from the soul, I would ask, “Is it from the soul of the father, the mother, or from both?” It neither proceeds from both, for there is no mixture of souls, nor does it proceed from one of the two, for then the question remains, “Does it proceed from the father or the mother?” This question one will not be able to answer. In what manner would it be transmitted from the soul of the parents? If the personal soul of one of the parents would be transmitted in its entirety, the parent would be without a soul. If the transmission were partial, the soul would be divisible, and having parts it would not be a spirit but a body. If one maintains that the soul is brought forth causaliter, that is, as the effecting cause, by the souls of the parents, the question must be asked, “Out of what?” It is neither produced seminally nor by the complete or partial transmission of the soul. It would then of necessity be brought forth out of nothing, which is not possible for that is a creative act which is the proper work of God alone. The comparison of a burning candle igniting another candle and thus transmitting its flame is not applicable here, as fire is material in nature. Thus, one candle transmits its flame to the other by way of molecular transmission, since it finds matter to feed upon.