When does the human being have a soul? Does the soul come into being at the moment of conception or does it have a pre-existence before it is united with the body? How do we understand the immortality of the soul?
Let us begin by clarifying what we mean when we speak of a human soul. We are using a Greek philosophical term, which Christian theologians have drawn on to speak about that unique, individual dimension to being human, which gives life, and which is the source of consciousness, conscience and will. Aristotle spoke of vegetable, animal and human souls; the human soul is that dimension that sets us apart from the rest of God’s creatures. The human soul is that which gives life to the earthly body and which is noticeably absent in someone who is dead. It is not limited by time or matter, so we can speak of it as being eternal, beyond time and thus immortal, and spiritual, as opposed to material. Its eternal, spiritual character allows us to have an intimate relationship with God and eternal life; it also binds us in a common humanity with all other men and women. It is that unique dimension that human beings share with God and therefore with one another. It enables us to make an eternal, fundamental disposition of our lives to be the loving servants of God in our earthly lives and to journey firmly on the path to our ultimate state of being ‘sons or daughters’ of God in eternity. In this sense we can see what we mean when we speak of the immortality of the soul and, as far as our knowledge will take us, of the pre-existence of our souls before they give life to our mortal bodies. We can also see the possibility and the awesome potential consequence of fundamentally rejecting our God-given, God-orientated status as bearers of this eternal dimension. Some Christian writers helpfully speak of the soul as ‘a spark of the divine light’ within each one of us and thus we can see the utter darkness that would follow if we extinguish it by our fundamental rejection of a relationship with God, the source of that light.
The exact timing of the arrival of the human soul in the body is unknown. As the ultimate gift of life, we can re-phrase this question as “when does human life begin?” The Greek philosopher, Aristotle, by virtue of the limits of observation that were available to him in his time, spoke of ‘ensoulment’ being at around one-hundred-and-twenty days into pregnancy. It is around this time that the foetus is fully formed and that the mother can experience independent movement by the child in her womb. This indication of the start of human life was upheld by Christian theologians and scientists until the modern period, when our scientific knowledge developed to understand that it is not quite such a simple matter. Aristotle thought that the man was the active partner, depositing fertile seed in the passive woman, who was the seed-bed in which it could grow. The modern science of genetics makes plain that both partners contribute equally to the genetic make-up of the child. This unique genetic package, which will develop into one or more human beings, exists from the moment of conception and so some scholars have held this to be the moment at which human life begins; as we are speaking of unique human beings, we can say that the eternal soul has arrived. This moment of conception represents ‘the safest option’ as it is the earliest possible moment that human life could begin, but the complexity of the question becomes clear when we consider that a significant proportion of fertilised eggs pass through a woman’s body and never develop into human beings. This has led other scholars to point to such subsequent moments for the start of a truly human life as being the embedding of the fertilised egg in the lining of the womb, or the beginning of cell division, of the laying down of the ‘primitive streak’ (only at this stage do we know if the pregnancy will lead to the birth of one or more human beings), or the point at which independent life outside the womb would be possible, or indeed, the moment when breathing beings as a sign of independent life. This scientific complexity does not take away from the fundamental point that it is that unique human dimension that we call ‘the soul’ that marks us out as being human and in an eternal relationship with God.