Which intrinsic criterion and which basic anthropology should we take as a point of departure in considering the embryo during the first week after conception? From what has been observed hitherto in this paper it emerges that the embryo during the first seven days of its life is 1) a being with its own life that is separate from the life of the mother; 2) a human being from a biological point of view; 3) an individual and 4) a being with an intrinsic finality.
However, can we also conclude that the embryo before implantation is a human individual or a human person? In his assessment of the status of the embryo in his encyclical Evangelium Vitae John Paul II, avoiding declaring expressly that the moment of animation coincides with conception, refers to the conclusions of modern biological science with a rhetorical question: Even if the presence of a spiritual soul cannot be ascertained by empirical data, the results themselves of research on the human embryo provide a ‘valuable indication for discerning by the use of reason a personal presence at the moment of the first appearance of human life: how could a human individual not be a human person? [Donum Vitae I,1] (Evangelium Vitae n. 60).
Taking as a point of departure the contemporary knowledge of embryology and above all of modern genetics, how can one not identify, by the use of reason, the early embryo with the human individual or with the human person?
The identification of the early embryo with the human individual or the human person
A solely materialistic explanation, such as that which typifies ‘identity theory’, on the specific functions of the human mind, is insufficient. The process of thinking, which is developed with abstract ideas, although dependent upon sensorial information, is in the final analysis an immaterial function. The same may be said of freedom: material processes, like chemical processes, which unfold according to a pre-determined model, do not explain freedom. Without a spiritual dimension, human freedom would not exist. Both man’s capacity for reason and his freedom pre-suppose that in him there is a spiritual principle of life. To be a human individual or a human person, the embryo must have both a spiritual dimension and a physical dimension. However, the presence of a spiritual dimension cannot be demonstrated through the method of research of the positive sciences. In an empirical way the spiritual dimension is ascertained only in the actualised capacity to perform functions that have in the final analysis their origin in the spirit of man.
In the embryo before implantation and after conception, manifest signs of a spiritual dimension are lacking. The process of thinking and the process of willing are functions in which both the spiritual dimension and the corporeal dimension of man have their own role, but in an integrated way. The content of rational consciousness is the symbols that derive from the sensorial experience of the environment and a person’s own body. The fact that this content is absent in the early embryo because of the fact that the sensorial organs are not sufficiently developed does not in itself exclude the possibility that the capacity to think and to will are already present in potential terms, a potential that will be gradually actualised in a way that is proportionate to the development of the senses. Indeed, we will attempt to demonstrate that it is difficult to think that the spiritual dimension is not present from the moment when the embryo manifests itself as a human being in a biological sense, that is to say from conception.
The specific identity
To return to the embryo before implantation, we must ask ourselves the following question: can we identify a being whose human biological nature alone is observed as a human individual or human person or not? According to the passage from the encyclical Evangelium Vitae quoted above, the contemporary knowledge of embryology and of genetics can provide a ‘valuable indication for discerning by the use of reason a personal presence at the moment of the first appearance of human life’ (EV, n. 60). How can these sciences be useful in discovering a personal presence in the human embryo from conception?
Whatever the case, the contemporary knowledge of embryology contradicts the classic notion in opposition to direct animation (and thus humanisation), a notion according to which the human embryo is said to begin its development as a coagulate of blood, that is to say as a non-living being, and thus a being that is not animated. Contemporary embryology confirms the view which holds that the human embryo, from conception, is a biologically human living being. To this should be added the fact that from conception the development of the embryo takes place in an autonomous, co-ordinated, continuous and gradual way. There are no caesuras in the successive process of development as there could be if there intervened during the course of the development of the embryo another mechanism of co-ordination or integration of the life of the embryo, to be interpreted as a moment when the embryo truly becomes a human individual by receiving a spiritual dimension.
Genetics has discovered the mechanism of this development of the embryo: beginning with conception the embryo is guided by the genome, the conception constitutes the result of the fusion of the chromosomes of the ovule with the chromosomes of the spermatozoon. Knowing that the genome is the most important foundation of the biological identity of a human being, we can ask ourselves what indications genetics can provide, in addition to the indications provided by embryology, to hold that the human embryo is a human person from fertilisation. In other words: is the presence of a fundamental biological identity conceivable without there being present the spiritual dimension that makes the embryo a human person?
The answer to this question depends on the anthropology that is taken as the point of departure. A dualistic anthropology such as identity theory identifies the human person with the mind or the human spirit. From this point of view, the presence of a biologically human being in itself does not imply the presence of a human person. A certain biological development can and must take place before the biological human being becomes a human person with a mind or human spirit. The physical/biological dimension is not seen as an intrinsic dimension of the human person.
According to the doctrine of the Church, which sees the human spirit (the soul) as the substantial (or better subsistent) form of the human individual, both the human spirit and the body are intrinsic dimensions of the human person. The genome as the deepest biological foundation of the body has, therefore, an intrinsic ‘role’ as regards the specific identity of man as an ‘embodied spirit’. Within this framework it is difficult to think of a stage in the development of the human embryo when the spiritual dimension does not exist, whereas the material dimension of the specific identity of man, or at least the biological-genetic identity, is already present. It is difficult to think this above all else because the human genome, as has already been observed in this paper, guides a development that is biologically human that is gradual, continuous and co-ordinated and which does not involve some caesura that could be indicated as the moment when a principle of truly human life, that is to say spiritual subsistent form, from that moment on takes on the guidance of further development.
The numeric identity
This argument also applies to the numeric identity, that is to say the identity by which human persons are distinguished from each other. In reading in a newspaper of the death of ten people because of a train crash I come to know about the generic character, the specific identity, of the victims, that is to say that they are human beings. In fact, however, they are individuals who, in having their own numeric identity, actualise this generic identity in a different way. In essential terms, the numeric identity means that this concrete individual with his or her own characteristics is a human person, independently of the state of his or her development, of his or her physical perfection, of his or her success or his or her defects. The numeric identity, at least from the external angle, can differ considerably during the various different stages of life. The cause of this is that the numeric identity depends upon the material/biological dimension of the human person.
Thomas Aquinas illustrates this when he explains a particular aspect of the numeric identity, that is to say intellectual capacity: this can differ notably between the various individuals of the human species and in the same human individual during the various stages of his or her development. What explains these differences? Taking as a premise that the human spirit (the soul) is the substantial form (or better the subsistent form) of the human individual, a human spirit that was different between human beings would have as a consequence that they, in not having the same generic identity, would not belong to the same species. Whatever the case, the capacity to think employing abstract concepts and the capacity to act freely are not in themselves different amongst human beings. The difference in intellectual capacity is explained with reference to the differences in the neuronal networks of the brain as a result of which the capacity to compute sensorial data can vary notably. In the final analysis the difference lies not in the capacity to think employing abstract concepts in itself but in the disposition of the material dimension of the human individual. The material dimension, therefore, is of determining important for the numeric identity.
Although the numeric identity, anyway externally, differs during life, what determines it fundamentally, although not solely, is the human genome, which is present and active from conception onwards. One understands that during the pre-implantation stage the embryo does not yet possess these neuronal networks given that the nervous system begins its development from the twenty-first day onwards. However, all the neuronal structures are already present in a virtual sense in the DNA from conception, including their contribution in a biological sense to the numeric identity of the human individual. We know that the neuronal networks are present in a virtual sense in the genome (even though other environmental factors also probably have their role in the anatomical and functional development of the brain). The DNA contains the biological basis of all the features that characterise the human being from conception until death.
We have seen that the presence of the genome from conception onwards is a sign of the presence of the spiritual dimension of that event. If this principle of human life is present the embryo from conception onwards has the specific identity of a human person. This means that the embryo is a human person under way, not a human person potentially, as regards its specific identity. The basis of the numeric identity is also actualised. This does not remove, however, the fact that the numeric identity involves a broad potential that is to be actualised. All the changes during the development of the numeric identity, because they do not involve a change in the specific identity, are not, however, substantial, but accidental.
An objection of Lanza and Donceel to this argument is that this implies a coincidence of a formal causality with an efficient causality of the spiritual dimension: the spiritual dimension, if present since conception, would be both the formal cause and the efficient cause of the human body. The formal cause cannot be the efficient cause of the generation of the thing of which it is the substantial form. Here it is useful to distinguish between generation and growth. Development subsequent to the moment of the beginning of existence is different from generation – it is growth. Growth is a process of a living being that has already been generated. The spiritual dimension, once the human body has been formed, is the moving principle, that is to say the efficient cause, of life. It is the root of all the processes of life, including the process of growth of the embryo.
In reflecting on this we can find a response to identity theory which is today the most widespread theory in secular bioethics and which says that there is a human person only when there is a presence of a manifest rational consciousness. The error of identity theory is that it confuses the manifest rational and autonomous consciousness, an aspect of the numeric identity that develops much later than conception, with specific identity, which has already been actualised since conception. It seems to be a contradiction but the manifest rational and autonomous consciousness is an accidental characteristic: an adult human person remains a human person with all connected rights even when the rational and autonomous consciousness has not yet developed or has never developed because of a grave mental handicap or has been irreversibly lost because of an injury to the higher part of the brain (the cortex or the higher cerebral nuclei). It is significant here that the adherents of identity theory on the basis of the belief that a human being deprived forever of a rational and autonomous consciousness is not a human person have proposed that anencephalic foetuses and patients in an irreversible coma (that is to say in a state of partial brain death) should be sources of organs for transplants. Although the numeric identity of anencephalic foetuses and patients in an irreversible coma differs a great deal from the numeric identity of human persons who have developed a normal rational and autonomous consciousness, they have, nonetheless, the actualised specific identity of a human person.