It is no longer a question of when a human being’s life begins. We have known since the mid- to late-1800s that human life begins at fertilization. It is simply no longer an open debate. We have scientific, empirical proof that this is so.
What is not quite so simple is the matter of the origins of the human soul.1 There are two main views among orthodox Christians regarding how the soul comes to be: creationism,2 which holds that the body and soul are simultaneously created at fertilization, and traducianism, which holds that both the body and soul are passed down from parents to offspring.
A third view (held by at least one early church father, Origen; some religions that do not hold to orthodox views, such as Mormonism and Islam; and some Jews) is that the soul exists before the body and is infused into the body once the body is created. However, there is no biblical support for this view, and the fifth ecumenical council may have condemned it as heretical in AD 553.3 I will not be considering this view in this article.
The word traducian comes from the Latin word tradux, meaning “branch of a vine.”4 As regards traducianism, it means that children are a “branch off” their parents. It is the view that both the body and the soul of a child are generated by the parents. The soul is still created by God, but indirectly, through the process of reproduction.
Tertullian was the first Christian to formulate the doctrine of traducianism. As creationism holds that an immaterial soul is conjoined with the physical body in a new creative act by God, traducianism holds that when God created Adam and Eve, everything in them, including the ability to create new human beings, was created.5
Norman Geisler is a modern defender of traducianism who presents many points of biblical and theological evidence for this view.6 In the interest of space, I will list six of his evidences. (1) Eve was made from Adam, not separately (Gen. 2:21–227). (2) Eve is called the “mother of all the living” (Gen. 3:20), an appropriate title if all other human life came from her. (3) The Bible speaks of the imputation of sin from Adam to his entire posterity (Rom. 5:13, 18). (4) We are born with a natural inclination to sin (Eph. 2:3; John 3:6). (5) Sin is universal. Why would all people be born in sin if sin is not inherited by all at birth? (6) The soul/body unity of human nature.
Geisler also presents four points of scientific evidence for traducianism,8 with the qualification that the words for soul in Hebrew and Greek (nephesh and psuche, respectively) mean life, and that a human life is a human soul. (1) It is a scientific fact that human life is passed on from parents to child by natural generation. (2) The possibility of human cloning argues in favor of traducianism, since cloning produces the same kind of life without a new creation. (3) Human souls, like animal souls, are passed on from parents to offspring. (4) Because humans are a psychosomatic unity (i.e., a soul/body composite), both parts of the person (the body and the soul) must be passed on from parents to offspring.
Objections to the Traducian View
Objections to this view of the origin of the soul include: (1) “The heart of the traducian view is that human life (soul) can be divided and passed on to others.”9 But this seems implausible. Only physical things are divisible. The soul is immaterial, so the soul cannot be divided.
(2) There are Scriptures that seem to teach creationism, so pointing to Scriptures that seem to teach traducianism is not the end of the matter. For example, it’s true that Eve was called the “mother of all the living,” but this could be equally true given creationism, since all human beings have Eve as a common ancestor. Also, it’s true that Eve was made from Adam, but she was not conceived by his sperm. So God would have had to supernaturally create her soul as well. The Scripture references used by traducians are inconclusive.
(3) Pointing to the body/soul unity of the human person is not decisive, either. Creationism is compatible with that view of human anthropology. In fact, Thomas Aquinas, one of the most well-known theologians who improved on the philosophy of Aristotle, was a creationist.
Creationism is the view that each soul is created directly and supernaturally by God. There have been different ideas about creationism presented depending on when human life is thought to come into existence. I will first look at arguments for placing the soul later in the development of the unborn human being and show why they must be rejected, then I will look at the arguments for creationism at fertilization.
Different points during human development have been argued for the occurrence of ensoulment. Some Christian writers allege that the soul is not present until (1) the embryo implants in the womb, since there is the possibility that an embryo can twin, or (2) quickening, the point at which the woman can feel the embryo move within her, or even (3) birth, since they say that God breathed into Adam the breath of life, and then Adam became a living soul. Sometimes much is made of ancient Christian thinkers (such as Thomas Aquinas) believing that ensoulment happens later than fertilization in pregnancy.
However, none of these are convincing. Not only has embryological science proven that human life begins at fertilization (which would mean the soul is present) but each later point presents difficulties. As Patrick Lee argues, when you split a flatworm in half, you get two flatworms. It does not follow from this fact that there was not one individual flatworm prior to the splitting.10 Additionally, what is often overlooked is that Christians still opposed abortion at all points during pregnancy just in case they were wrong about the point at which the soul is present in the body. The ancient Christians were relying on the science of the time and ancient Greek ideas about how the body comes about. The science of embryology did not show that human life actually begins at fertilization until the nineteenth century. If Aquinas had known about nineteenth-century embryology, he certainly would have agreed that the soul is present in the body at fertilization. Finally, the “breath of life” argument is a very specious one. The most obvious reason is that respiration does take place in the womb — only the method of breathing, not the fact of it, changes at birth. In the womb, the embryo/fetus takes in oxygen via the umbilical cord. Also, Adam was not created like other human beings. Adam was created already in the outside world, so he had to be able to breathe in order to survive. We can’t take this as a normative claim about ensoulment, especially in light of the scientific evidence we have that life begins at fertilization.
Since the scientific consensus among relevant experts is that human life begins biologically at conception and that all of a person’s genetic information is present at fertilization, and since the soul is the factor that makes a human being alive, the most plausible point of ensoulment is the moment of conception. Furthermore, in my view this reasoning plausibly implies creationism.
Philosophically, as a thought experiment, think of a glob of rubber. You can fashion that glob of rubber into a rubber ball. In that case, the material cause of the ball is the rubber it is fashioned from and the formal cause is its “ballness.” Its material gives it certain potentials, such as its potential to bounce and be melted down, and its form gives it certain potentials, such as its potential to roll. The ball doesn’t exist as a ball, however, until the matter takes on the form of a ball. Therefore, it follows that a human soul begins at fertilization once it takes on the form of human being.11 And since the human soul has spiritual capacities, such as the capacity to commune with God, and is immaterial, it cannot be created by material processes. Thus, God must supernaturally create both the soul and body.
Objections to the Creationist View
Traducians usually raise the following objections to creationism:12 (1) Creation was completed on the sixth day (Gen. 2:2; Deut. 4:32; Matt. 13:35), and God is resting and has not created since He finished (Heb. 4:4). (2) Creationism makes God the direct author of moral evil, as it would imply that God, who creates a pure soul, puts that soul into a body that will inevitably corrupt it. (3) The creationist view does not explain the inheritance of original sin. A perfect God cannot create a fallen soul, and to believe that the body is corrupted by contact with the soul, which precipitates its fall, is a gnostic view and is unacceptable as a Christian view. So, both body and soul must be naturally generated from one’s parents.
An ancient debate among Christian thinkers, creationism versus traducianism is still hotly debated today among Christians of all stripes. While both positions have able defenders, both positions also have weaknesses. The proponent of traducianism has difficulty explaining how an immaterial soul can be passed down through a material process, and the proponent of creationism has difficulty explaining how original sin can be passed down from Adam to the descendants of Adam. That the immaterial human soul exists is inviolate. How the soul comes to be remains, ultimately, a mystery.