This brief intervention intends to clarify the following question: is the human embryo a person?1 By embryo I mean a human being after its conception, or, in other words, after fertilization. Moreover, a zygote is readily called a â?? one-cell embryo â?? today. Later I will define what I mean by the name person. To respond to the question raised, I will only refer to data from the sciences and philosophy. I will thus leave aside the properly theological approach and all the more willingly because the Catholic Church invites us to do this: â?? How could a human individual not be a human person? The Magisterium has not expressly committed itself to an affirmation of a philosophical nature â??.2 Lastly, in order to clarify the subject as much as possible, it will be presented in the rigorous form of a quaestio disputata.

STATUS QUESTIONIS

The negative response

At first glance, it seems that the answer is negative. In this perspective, a zygote has to pass through a certain number of stages before it can be qualified as fully or really human.3 According to the criteria of humanization chosen, an embryo becomes a full-fledged subject: when the two genetic patrimonies of paternal and maternal origin recombine in the new genome of the embryo, or between 21-22 hours after fertilization;4 after implantation;5 on the fourteenth day6 when all totipotentiality has disappeared and the primitive line emerges;7 when the unity of the human organism becomes irrevocably signified by the emergence of an organization and the impossibility for homozygote twins to form between the 14thand the 18th day;8 when the principal organs come into being (the eighth week);9 when some electro-encephalographic activity is detected;10 when the brain becomes capable of certain functions such as sensation, memory or learning (twentieth week);11 â?? at the stage of maturation that allows autonomous life â??;12 that is, at the sixth or seventh month,13 when self- awareness sets in for which a date much later after birth cannot be fixed;14 the criterion of parentsâ?? recognition which is even more variable if it requires knowledge about the existence of the zygote and so is necessarily after its emergence.15 Lastly, there are those who affirm the continuity between gametes and zygote and thus make human individuality refer back to them.16

Logic teaches us that the crux of a demonstration lies in its middle term, not its conclusion. Given that in the name of the same argument, sometimes two different dates are put forward, I will distribute the demonstrations in a way that is not contingent on this calendar of access to humanization â?? of which the multiform distribution shows that it is somewhat uncertain â?? but on arguments.

I will isolate six of these arguments, of which the first five are the most common ones. I will develop the sixth because it is still somewhat present among Catholics, and this will enable me to enter into the debate with the Thomist philosophers.

The possibility of homozygote twins

A person is an individual and so etymologically he is an indivisible being. Now, an embryo is divisible, at least up to fifteen days, as the existence of homozygote twins shows: that is, twins that come from the same initial cell. So an embryo is not a human person. One cannot speak about a human person until the possibility of the emergence of real twins has passed. â?? If we consider that a fertilized ovum is a person â??, wrote Xavier Thévenot: â?? How then can it be accounted for philosophically and theologically that in the case of a split into twins (which is possible up to 14 days after conception) one person can become two persons? How can a reality whose individuality is not even certain be considered a person? â??.17

The presence of totipotent cells

A complete living individual is a differentiated organism made up of many organs ordained to one or more functions. Until the eight cell stage,18 the embryo is made up of totipotent cells: that is, cells capable of becoming any organ. Therefore, in the beginning, we are not in the presence of a fully constituted individual, a fortiori a human person.

The need for a conscience

A person is an individual capable of suffering, relations, reason, freedom, etc.19 To exercise one of these abilities supposes the presence of a brain. But the central nervous system does not begin to be formed until six to eight weeks after the fusion of the gametes. So as long as it is not endowed with a brain, an embryo is not a person.20

The argument can be refined based on Paul Ricoeurâ??s position in his principal book: â??Soi-meme comme une autreâ??. The hermeneutics of self are caught up in a dialectic of sameness and ipseity that is resolved in the concept of narrative identity. In other words, the self has access to its ipseity through narration. In fact, the constitution of self, grasping its permanence, is declined in two versions: identity as sameness (or identity-idem) to which responds a permanence of the substratum, and identity as ipseity (or identity-ipse) to which narrative permanence responds. The first permanence introduces some unsolvable apories.21 So the question can only be answered â?? yes â?? by referring to another kind of permanence that is introduced by the word through which the subject enters into self-possession and understanding of self.22 Quite obviously an embryo has an identity-idem; it does not have an identity-ipse. Its self cannot be narrated. Consequently, the embryo cannot be human from the outset.

The need for recognition by others

 The I is only awakened by a You that recognizes it, in this case, the parents. This recognition of the new life has nothing spontaneous about it: it implies a desire for a child and a parental project. Therefore, an embryo only becomes a person in certain conditions defined by its parents. â?? An embryo becomes a person under two conditions â??, explains professor Rene Frydman. â?? It must have the physiological abilities to develop and it must be accepted. It only belongs to the desire of the people who have elaborated it in thought and in practice. A woman decides in conscience whether or not she wants to bear it. A destiny cannot be found for embryos against the parentsâ?? willâ?¦What is important are democracy and dignity â??.23

The frequency of spontaneous abortions

 The spontaneous abortions that occur during the first days of ontogenesis are numerous.24 What is natural comes about more often than what is not. Isnâ??t the extreme regularity of physical laws a criterion of their naturalness? Consequently, it would be against nature for a zygote to be a human person. Based on the figure of half the non-implanted fertilized cells, the theologian Karl Rahner asks: â?? How can it be thought that 50% of human beingsâ?¦never get beyond a priori this first stage of human existence? â??.25

The need for an organized body

 I will present this argument in detail because of the fact that it is common among philosophers of a Thomist school â?? at least since the 70s.26 The apory can be formulated based on the Aristotelian definition of the vital principle. The soul is the first act of an organized body. Now, a zygote and an embryo in their first stages do not present sufficient organization to perform an operation preparing for intellective life. So an embryo is not a suitable subject for a human soul.27

Benedicte Mathonat refines the argument. The starting point is once again the Aristotelian definition of the soul: â?? The body, the subject of the soulâ?¦is organizedâ??. To be organized is to be a principle of operation: â?? The organization in question isâ?¦that which manifests the bodyâ??s power to operate â??. â?? The body, the subject of the soul, is thus one that is capable of carrying out the operations of human life â??. The operation proper to human life is intellectual operation. But â?? the human intellect only has knowledge based on the senses â??. So, â?? the human soul has for its own subject a sensible body â??. But the nervous system is the organic principle of sensibility.28 Therefore, to be informed by a human soul, an embryo must have a nervous system. It is quite obvious that this is lacking at the starting point.29

The objection will be made, however, that far from trying to find a way to get around the magisterial teaching, Aline Lizotte30 defends herself expressly for not presenting a doctrine coherent in any way with the Magisterium, especially with Donum Vitae. The exhortation requires that Godâ??s creative presence be discerned from conception. Doesnâ??t mediatist infusion reject this?

The response to this objection is another original contribution of the article. Inspired by Aristotle, Aline Lizotte distinguishes two modes of presence of the soul in the embryo: according to formal causality and according to final causality. The soul is present in the body according to the first modality (formal) when it is united to it as a potential act that receives it, like the form to the matter that is proportioned to it, in view of constituting a being that is substantially one, with an intrinsic unity that rejects all dualism. The soul is present in the body according to the second modality (final) when it guides the entire becoming as an attractive and actualizing end. The finality, in the full Aristotelian meaning, is surely a term, a result, and even the effect par excellence, but it is much more than this: in fact, before being an effect, the end is a cause. A cause only acts through its reality; it only gets its efficacy from its effectiveness. So it is endowed with a kind of realism which, for lack of comprehension, a considerable number of current concepts have passably exhausted. In other words, the presence by way of finality is a very real presence. It can be said that the end is present intentionally if intentional is not opposed to real.

THE POSITIVE RESPONSE

However, some facts put the thesis of a differed personalization up for question.

The precocity of intrauterine life

 Today physiology and psychology take into consideration more and more the life of the little man even in intrauterine life.31 From the dawn of the â?? self â??, it appears that the fetus is already capable of feeling, sensing, imagining and memorizing, as established by one of the speakers at the colloquium, prof. Bellieni.32 An ever-growing body of facts also suggests recognizing the occurrence of psychic traumas in a period that is closer and closer to conception. 33 Doctor Benoit Bayle, a practicing hospital psychiatrist in the Henri Ey Hospital Center in Chartres, believes that some phenomena of embryonic life seriously hamper the development of the future child or adultâ??s personality. Those who speak about subjective experience indicate, even in words, the existence of a subject that lives the experience. This is why dr. Bayle speaks about psycho genome and conceptional scene.34

The trauma of abortion

 Today the traumas connected with voluntary (and even spontaneous) interruptions of pregnancy cannot be denied. In one remarkable recent work on abortion, the sociologist Luc Boltanski recalls this and, at the same time, shows the many strategies set up by society to close its eyes to the humanity of the embryo in order to eliminate it better.35

The wound of exclusion

 We are very sensitive to any form of exclusion, and this is good, especially of the most vulnerable persons. Now, no one is more vulnerable and more innocent than a new being in its motherâ??s womb.36 â?? The only way to be fair with life is to respect the smallest of the living â??.37 It could thus be said that the good health of a society is judged by its ability to welcome this eminently fragile being which is the human embryo. Moreover, there is a striking parallelism between the current reasoning to justify the use of embryos in the eyes of politicians and the people in the name of their presumed lack of human nature, and the reasoning used five hundred years ago with regard to the nature of the Indians of Latin America. Both are vulnerable beings which our desire for power runs the risk of eradicating. King Charles V and his Council were shocked to learn about the inhuman treatment inflicted on the Indians. But, to put it briefly, since he needed money to wage his wars, he did not totally reform the â?? Indian â?? laws. In the same way, many political or medical personalities think that the embryo constitutes the first stage of a human person, but they hide behind the potential profits from research for the sick, the need to keep pharmaceutical laboratories in their country, etc.38

RESPONSE

We are sorely lacking a philosophy of nature adapted to the newness not only of the cosmological vision brought by the many scientific discoveries over the past century, but also to the demands for ethical regulation with regard to technology.

I would like to propose four arguments that will be presented in a progressive and apparently exclusive way. In reality, they seem complementary to me, and I hope that the limits of one will be compensated by the limits of the other. I will introduce them with a brief, particularly epistemological introduction.

 Preliminary conditions

 The strictly philosophical reasoning that I am going to develop implies two preliminary conditions. The first is of a scientific order. I will presuppose the many developments that have been made, with their known authority, by professors Colombo, Sica and Bellieni, regarding fertilization (thus the emergence of a zygote or single cell embryo) and the first stages of embryonic life. The second preliminary condition is of an epistemological order.39 This has to do with the link between philosophy and science. To state it simply, we are before two equally partial and thus biased positions.

The first position of continuity considers that there is a passage with no break from scientific facts to philosophy: for our subject, that is, to the question of the identity of the embryo. But this position, which is basically scientist, leads to the worse consequences. It underlies most of the mediatist positions. It denies any differences in views.40

Following Emile Boutroux, Maurice Blondel makes a strong critique of scientism. The sciences join calculation and experience in their method, experimentation and argumentation, empiricism and formalization, but how can the success of this wedding be explained? Science uses this felicitous harmony: moreover, it lives it daily, but it does not take it into consideration.41 This wedding shows spirit: â?? Our sciences do not bring or make the world and man. It is man who makes science, who dominates it always, just as he dominates, even without but better with this universe in which he seems immersed, but which he always infinitely surpasses with just one surge of his thought or one act of his freedom. It is not the world that questions and commands us, nor does it produce science; it is we who make science and throughout the world ask ourselves about another mystery different from the one the scientists ponder â??.42 So the spirit is â?? that power without bounds in this infirmity without remedy â??, which are the sciences.43

The second position, which is the complete opposite, considers that the two types of disciplines are in discontinuity. An epistemological position of this kind supports, for example, the reasoning of some Thomist philosophers. 44 To state it briefly, philosophy is to the sciences what universal affirmations based on common sense are to more particular affirmations based on hypotheses, even paradigmatic categories. The degree of certitude is a func- tion of universality and foundation on very common facts.45 But a position of this kind leads to a dualism that makes the fields of learning watertight and is refuted in practice.

So we cannot do without an epistemological reflection and an attempt to articulate the two fields of knowledge, while respecting both their autonomy and their interaction and, we dare say, their hierarchy.46 On this subject, it could be enlightening to refer to Maurice Blondel again â?? precisely, the distinction between the two types of thought, noetic and pneumatic.47 It is obvious, writes Georges Cottier, â?? that the philosopher of nature who studies, from his viewpoint, the origin and genesis of the living, must have first hand information at his disposal about the results and the development of scientific research. This is a necessary condition for the validity of his reflection. He must prove to be ready to make revisions because the philosophy of nature, like science, is measured against the duly certified facts â??. While confirming that science enriches philosophy from within and not laterally through the great amount of facts it brings, he adds: â?? This, however, does not mean renouncing hastily, and without making a serious confrontation with the scientific facts, some intuitions of a philosophical nature which are knowledge acquired from the heritage of Aristotle and here of Saint Thomas in particular â??.48

THE PERSON AS AN INDIVIDUAL

Presentation

 To speak about a person is to speak about an individual being of the human species, and individuality is characterized by this dual note: uniqueness (divisum ab alio) and indivisibility (indivisum in se).

Embryology and genetics show us that from conception, the embryo constitutes: a being with a specific nature, in this case a human nature, different from any other animal and living species, for example, from that of the pongids (chimpanzee, gorilla, orangutan); and an individual being, both unique and distinct from any other49 â?? individual and original, in its genome and its phenotypic expression. This is all the more true of the embryo which, in its development, manifests, on the one hand, its indivisibility more (when the possibility of real twins disappears), and, on the other, gains in originality (by making unique relations with the environment that shape its morphology or re-echo on the genome; and even more by appropriating the biological datum one day through its freedom and thus in a relationship).50

So it must be firmly asserted that the human zygote is an individual. And this individuality must be qualified as human because the genetic characteristics are specific before they are individual. Lastly, it must be said that this individuality is personal.

The argumentation is based implicitly on totality and continuity. In the name of totality: â?? Since the human person is a whole â?? body, spirit, soul â??, as a nurse writes, â?? it would seem logical to think that this developing human life already has that indivisible wholeâ?¦Isnâ??t an embryo also apparently different from a newborn just as a newborn is different from a forty year-old man? And yet it is and always will be the same person, genetically defined forever, until his biological death â??.51 In the name of continuity: â??Today, if the embryo is sacred â??, says the gynecologist Jacques Milliez, â?? this is from the formation of the zygote. There is in fact an absolute continuum of phenomena from fertilization which creates no more doubt for scientists â??.52

Limits

 Is it sufficient to show that a zygote is a human individual in order to conclude that it is a human person? The assertion that from fertilization until death, without interruption, the embryo is fully endowed with individuality, in order to conclude with its spiritual nature, raises some questions.53

In fact, this argumentation is supported by a philosophical presupposition that could be described as Parmenidian. It stresses continuity, even sameness. It overlooks the emergence of real new elements, and these are rightly indicated by the supporters of a differed personalization: uterine implantation and exchanges with the mother, indivisibility, the neural plaque, the organs, especially the brain, the conscience, the parental project, recognition by others. In what name are these novelties devalued, or even denied? Moreover, this continuity holds for a genome, and in what name should a genome be given value against the phenotypic and epigenetic determinations? Furthermore, these new features are only potentially present. In this way we come to the difficulties of defining an embryo as a potential person. Lastly, the continuity in question only results from what is observable. The considerable break implied by generation or corruption defies the solely empirical viewpoint: this is true of death. It is also true, on the other hand, about the emergence of life. Consequently, the failure to observe a break in development does not mean at all that a substantial becoming has not come about, in this case the irruption of an intellective soul. Deep down, we find the dilemma again that set Parmenides of Elea against Heraclites of Ephesus, at least in the way it was systematized by Aristotle.54 Its solution, in any case, needs to be questioned. Doesnâ??t the conception of otherness and history underlying the criterion of continuity result from a problem of identity-idem, to use Ricoeurâ??s words?

In addition, let us take up the traditional definition of person proposed by Boethius, which has profoundly marked the West. While it was made for the needs of Christology, its perspective is strictly rational: â??The person, he says, is the individual substance of rational nature â??.55 The above approach stresses individuality directly, but it only shows rationality indirectly, based on continuity. Consequently, it cannot be said that the zygote is a person.

Lastly, it can be asked if the argument is not too remote. In fact, it is based on the notion of individuality, which is metaphysical, when the question refers to the field proper to the philosophy of nature and even bio-philosophy. A reasoning is conclusive if it gives its own reason, which is proximate.56

Above, while the neo-Aristotelians and neo-Thomists favorable to a mediatist personalization affirm very strongly the human individuality of the embryo and its continuity after conception, they oblige us to refine our approach to the human being. In dialogue with them I will now proceed.

The person as an organized body animated by a spirit

 Based on and postulating the Aristotelian definition of the soul as the life principle, the next two paragraphs will seem to many researchers and even non-scientists to reawaken in a naive way an issue from another era, or even the polemics caused by vitalism, which the advances in the biological sciences, especially genetics and molecular biology, seemed to have definitively averted. However, I do not believe that this approach is useless, even if it requires a significant up dating and a patient captatio benevolentiae. First, it is still used by the Thomist (and the Aristotelian) supporters of the mediatist position.57

Next, it makes it possible to respond to the last objection (the proportion of the argumentation). Moreover, the paradox of life,58 the apories of biological reductionism,59 the significant multiplicity of explicative models of life,60 the â?? ontological complexity â??61 of a â?? mosaic world â??62 show indirectly that the theme in question cannot be declared obsolete so readily, or at least that a place is left for approaches other than the ones proposed today. Lastly, on the purely philosophical level, the sole cosmological perspective continues to be insufficient. This is why we will frame it with two other approaches: the first is more metaphysical and the second more phenomenological.

Statement

 As we know, Aristotle distinguished living beings from inert beings, the former having a life principle called the soul. In a properly classic definition, Aristotle defined it as the first act of an organized body.63 This definition asserts two things in particular: on the one hand, the psuchè is an act, a form; on the other, it exercises its action on a fit subject: namely, a body that is sufficiently differentiated and functional to be a principle of the operations proper to the living being, in other words, an organized body or organism. Obviously, the fertilized cell has a real structural organization, with different levels of integration from the nucleotide to the cell in its totality, passing through the gene, the genome in its totality. Consequently, the one-cell embryo is the subject of a human, spiritual soul. Let us develop this argument.

What is an organized body?

 To explain the meaning of the term organ, it seems best to me to refer to the detailed explanation that Thomas gives of the term organized when he comments on Aristotleâ??s definition of the soul in his Peri psuchès:64 â?? Next Aristotle comes to this part of the definition that deals with the subject of the soul. Just as he said that the soul is the act of a physical body that has potential life, he says again that this describes any organized body. He calls an organized body one that has a diversity of organs. This diversity of organs is necessary to the body, the subject of life, because of the diversity of operations of the soul (Diversitas autem organorum necessaria est in corpore suscipiente vitam propter diversas operationes animae). In fact, since the soul is the most perfect form among the forms of corporal beings, it is the principle of different operations. It thus requires a diversity of organs for its perfectibility. On the other hand, the forms of inanimate things, because of their imperfection, are principles of few operations; hence they do not require this diversity of organs in keeping with their perfection â??.65

An organ is thus defined as a material principle of operation, here the operational principle of the living being. Organ often evokes a structure first of all. However, the term has a meaning that is not only static but also dynamic. The Greek etymology, organon, means â?? instrument â??. For Aristotle, an organ is a physical instrument moved by the principal cause, which is the soul in view of its finality, the vital operation, what presentday biology calls function. And if a living body is necessarily an organized body, the reason is as follows: to be organized is to be endowed with many organs. Contrary to an inert being, a living being must carry out a great number of operations, starting with the fundamental operations of life like assimilation. But, as we have just said, an organ is the material instrument, the principle of operation. This is why an animated body is an organized body.

Furthermore, three degrees of life can be distinguished: vegetative, sensible and intellective.66 The preceding principles make it possible to specify the nature of the organized body that is needed according to the type of living being. A living body will be informed by a vegetative soul (in other words, it will be a vegetable) only if it is suited to vegetative operations and hence endowed with organs that carry out these actions: namely, for Aristotle, nutrition, growth and generation. In the same way, an animated body will only be able to be actualized by a sensitive soul (characteristic of an animal) if it has the degree of organization sufficient to carry out the operations proper to animal life: that is, sensation in the least, and the first and fundamental sensation is touch. Lastly, a spiritual soul that carries out the operations that do not depend on matter does not have an organ of its own. On the other hand, it requires a perfection of sensible life and of its organs sufficient to prepare the acts of intelligence and will adequately. This is why it is impossible to think without the presence of a brain even though it is not the organ of thought.

As we can see, the realism of Aristotelian hylemorphism calls for more than individuation in order to speak about a living being. This individuality of the living body is a necessary but insufficient condition to speak about an animated being. The soul is the principle of being but also of operation. The body united to it, according to its own mode as the material cause, is also informed by the soul and the instrument directed by it, and so it is equipped for this end: in a word, it is organized.

Is the zygote an organized body?

 So the question raised is made clear: does the fertilized cell have the organic perfection, that is, the organization, which enables it to be the (material) principle of operation of a spiritual soul? No, answer the disciples of Saint Thomas favorable to mediatist animation (and with them a considerable number of supporters of other philosophical or implicitly Aristotelian tendencies). In fact, these operations cannot be carried out without the presence of organs, especially the central nervous system and above all the brain. This is why a zygote without these organs is still not fit enough to be informed by a human soul.

On my part, I believe that it is necessary to answer yes in view of the knowledge acquired from the biological sciences and interpreted philosophically. This is for two reasons: 1) a structural reason (affecting being), 2) and a functional reason (concerning acting).

1) Some speak about organization, some differentiated complexity: in other words, system. As we have seen, in the example of any cell, a zygote has a structure of an unprecedented complexity and organization that defies any current attempt to establish a model. This specialized structuring holds both for the genome present in the nucleus and for the cytoplasm, the structure of which has been revealed by tomography through electronic cryomicroscopy (with high spatial resolution).67 Far from being encumbered chaos, this complex ordering is structured. Doesnâ??t it respond to the need for organization of the subject of the human soul? Moreover, our morphological knowledge about the cell taken separately shows us an organization that is much more complete and complex than what the ancients knew about the human body in its totality, but they did not refuse to make the body the matter of the rational soul.

Moreover, Thomas Aquinas saw in this harmonious complexity the specificity of the human body and the reason for which it is the proportioned subject of the spiritual soul: â?? It was necessary for the body to which the intellective soul is united to be a mixed body and, among all the others, the one that received the most balanced composition (aequalitatem complexionis) â??.68 So the argumentation still holds today and the zygote can receive this spiritual soul.

Above all, it is recalled that in the end Aristotle stated that the embryo is only â?? an assembling of undifferentiated flesh â??.69 In fact, â?? the first combination of a female and a male is called an embryo â??.70 To the point that it can be called a larva: â?? In one sense, it seems that almost all beings generate a product that starts out as a larva: the embryo in its most imperfect form is in fact something like a larva, and among the whole of viviparous and oviparous beings whose eggs are complete, the embryo is indistinct at first and then it develops â??.71 Based on the experience of the emergence of the first movement, as well as on the observation of aborted embryos, Aristotle, followed by Thomas, thought that â?? conception (that is, the presence of a human soul) was acquired at forty days for a male embryo and at ninety days for a female embryo, but not without great variations among individuals. 72 While what was known at the time about the organic structuring of a forty or ninety day embryo was very real,73 it was extremely rudimentary and much sketchier than what the least of our cells reveals. And yet, it was enough for the Stagirite.

Who would dare to deny that a one-cell animal (protozoan or protophyte) is living if Aristotleâ??s ever-valid distribution is used, and if it performs the three operations of nutrition, growth and reproduction? Quite obviously, does a protozoan or a protophyte have any visible or even differ- entiable organs? So an organized body is not identified with a body endowed with visible and isolated, identifiable organs. This is not to say that Aristotleâ??s definition is wrong: an organic body continues to be the necessary subject for life; an organ continues to be the principle of vital operation, as we shall say again. On the other hand, the adjective â?? organic â?? and the term â?? organ â?? can no longer be tied only to morphologically identifiable reality, as the philosopher of Stagira did. And what is true of vegetative operation is also true of the sensitive act: animal life begins and exists before the eyes can perceive it. This no longer refers to an organism in the sense of differentiated entities. But in this way we have already anticipated the second point.

2) An organ is defined by its structure, but even more by its function, its finality: namely, to be a principle of action. Are the operations that authorize the structure of a fertilized egg proper to man? Can a human zygote be the principle of operations proper to a rational living being?

It could be claimed that structure (morphology) is to functioning (physiology) what the first act is to the second act. One is as one acts, according to the scholastic axiom already enunciated. In reality, an argument of this kind is too universal to come to a conclusion: it is borrowed from metaphysics and is not proportioned to our question, which refers to the philosophy of nature. However, it should not be discarded: if Aristotle and Thomas thought that the slightly differentiated structure of a forty day old embryo was a principle of operation sufficient to be the subject of a human soul, what would they say today in view of the extraordinarily complex structures of the cell? In fact, the operations of the zygote are of a complexity commensurate with its structure. To the most complex genome of the living world, which is human DNA, corresponds the most sophisticated activity of the so-called biological universe.

First, the biological sciences teach us that the zygote is intensely active from the beginning. It performs the metabolic functions characteristic of all living beings. So it is in the least the subject of a vegetative soul.

Next, until we are more fully informed, we unfortunately do not have studies regarding the sensitive operations of the zygote (human or animal). The only observation, for example, of elementary tactile sensation would oblige us to conclude, in a definitive way, that this living being is informed in the least by a sensitive soul, or to take up the more precise formulation of the Contra Gentiles again, that it lives an animal life. The fact remains, however, that a zygote has everything a protozoal eukaryote has and noth- ing of a protophyte.74 Now â?? and this fact is worth stressing â?? protozoans are proof of sensibility, in this case, tactile knowledge, and, for some, of mobility.

Finally, is it necessary to take the decisive step and say that, even without neurons and a brain, the union of the human ovum and spermatozoid is fit to receive a spiritual principle? How can it be asserted that the zygote performs acts of intelligence and will? But this is not required either by Thomas or by his disciples who support mediatist animation (if not, a child at birth would still not be a human being!). It could be answered that the sensitive operations are acts of the body-soul combination, while the operations of the spirit call for being free from all material causality, all corporeity. Consequently, it is possible to assert the presence of a concomitant spiritual soul. But it is possible to say more, and it should be said on behalf of the human soul that although it is spiritual, it remains the act of the body. The unity of the person requires a human body to be fit to be informed by a spiritual soul. So it must differ from the solely animal organism that reduces a solely sensible soul to the act. In fact, the organization of the zygote is the principle of sensible operations that prepare the spiritual acts. In reality, the genome of the fertilized egg, from the fusion of the gametes, contains all the information within itself: that is, the plan of organization, in view of building the organism, in particular the prefrontal cortex which, through the mediation of the internal senses, prepares for the operations of the spirit. Moreover, from being passively stored, this information unfolds, from fertilization, in immediate and tireless activity. As François Jacob wrote thirty years ago: â?? Each egg thus contains in the chromosomes received from its parents, its whole future, and the stages of its development, the form and the properties of the being that will emerge from it. The organism thus becomes the realization of a program prescribed through heredity. For the sake of a Psychè the translation of a message has been substituted â??.75 It is not by chance that the great book of the Nobel Prize for medicine describes the history of biology as an marvelous plunge into the more and more microscopic structures of the living. This is undoubtedly a consequence of the reductionist method, but it can also be interpreted as a tribute to the miniaturized determination of the living, and more precisely, the differentiated hierarchy of the degrees of determination present in the animated being.

The preceding facts suggest stating clearly that from fertilization an embryo is a person. Not a potential person, as the Consultative Committee of Ethics says, but a person with a potential. This assertion is based on the fully human character of the body. The human zygote is the organized body suitable to receive a spiritual and immortal soul as its first act.

Objection

 The following objection has been made to this demonstration: the above argument is based on the initial activity of the zygote. Some animal species are endowed with a genome that is almost as complex and active. Consequently, from the beginning, a human zygote does not present any specificity with regard to the fertilized animal egg. Why then would it be informed by a spiritual soul? â?? The extraordinary activity of which the embryo is capable from its very first stages, from fertilization â??, writes Georges Cottier, â?? does not yet constitute proof of the presence of a spiritual soul. In fact, a similar active power is found in the embryos of other animal species â??.76 Another difficulty could be added: our argument is based even more on the complex organization of the genome. The human zygote shares this structural complexity in particular with the chimpanzee since 98.4% of the genes are common between the human species and that of these pongids. This can be stated differently: everything in the complete human body signifies its humanity. Aristotle already showed this with great accuracy of observation, from the fine grain of manâ??s skin to his vertical stance, passing through his articulated voice and the opening of his mouth.77 Now, in reverse, nothing in the zygote or in its genome manifests this difference.

Response

 These arguments are all the more impressive because they are given in figures and seem to lead to the following comparison: man differs from an animal by just a little more than one percent. â?? The major error (often made) â??, retorts the biologist Jean-Didier Vincent, â?? consists in saying that we are 99% comparable to chimpanzees â??.78

First of all, the quantity is not negligible. The human genome is made up of 3 billion nucleotidic bases. According to the latest estimates, the difference is 1.2% and so there are less than 40 million nucleotides of difference between man and chimpanzees.

Second, the quantity does not tell us everything. The order must also be taken into consideration. The direct analysis of portions of the genome shows that there are selective mutations within genes (one nucleotide being replaced by another),79 insertions or disappearances of short sequences of DNA,80 duplications of fragments of genes,81 and rearrangements of entire pieces of chromosomes.82 Put end to end, all these elements make the genetic distance between man and the chimpanzee rise to 5%. Consequently, Svante Paabo, the Director of the Department of Genetics at the Max-Planck Institute of the Anthropology of Evolution in Leipzig, states: â?? This small 1.2% (difference between the DNA sequences of man and the chimpanzee) can mean a lot, especially if the different rearrangements, duplications and deletions observed are added to the 40 million selective mutations â??.83

Along the same line of ideas, while the genes resemble one another very much, the karyotypes differ: manâ??s includes 46 chromosomes, that of the chimpanzee 48, and that of certain species of monkeys up to 70. The differences in the architecture of the chromosome bring a difference in the expression of the genes and so also of the regulator genes on which many genes depend.

Furthermore, proximity and genetic similarity are not troubling unless they are interpreted in a naively linear and analytical way. Now genetics is oriented more and more towards not a linear, but rather a combinatorial, even a â?? systemic â?? understanding of the genome.84 â?? The combining effect of the genes explains how small genetic differences can have considerable consequences on beings â??, as the geneticist Axel Kahn notes.85

The problem raised by the continuity between human and animal genomes is also considerably intriguing to experts in neurogenesis in particular. They in fact come up against one troubling paradox.86 To state it simply, from a worm to a mouse the number of genes increases from six to eight times. On the other hand, from a mouse to Man, the number stays approximately constant, that is, around thirty thousand genes. An even stranger fact is that judging from the available observations, they seem to be relatively similar. However, it is obvious that these two organisms have profoundly different brains: 87 from a mouse to a man, the surface and the layers of the prefrontal cortex (or the front part of the brain) have grown considerably, going from a few per cent to almost 30%.88 Therefore, apart from the philosophical question regarding the moment of the zygoteâ??s animation, this non-linearity raises an apory that requires a solution on a strictly scientific level. In this case, two explanations seem to be proposed at present: the first is of a combinatorial order: it seems that a great reserve exists in the 30,000 genes; the second, which takes time into consideration, is of a sequential order: the genes are not expressed only once but many times over the course of development.

Although spectacular in its results, the difference can be very economical in its means: that of the critical role played by certain genes in the separation of the species. For example, one gene codes the enzyme called CMAH. The function of this enzyme is to help to add a particular sugar, sialic acid, to the surface of the cells. In humans, different from primates, a mutation has affected this gene. Consequently, the CMAH cannot be coded. A study coor- dinated by Ajit Varki from the University of California in San Diego, has shown that this inactivation of the gene undoubtedly took place a little before the spectacular growth of the brain in hominids, or even two million years ago. This concordance in time makes it possible to suggest that the mutation of the gene of CMAH may have played a role in the increase in brain volume. 89 Be that as it may, this hypothesis shows that a small cause (genetic) is capable of generating great effects (phenotypic).90

Finally, it is not pointless to recall the epistemological need for a correct distinction between scientific and philosophical discourses: to conclude from the slight genetic distance between man and a chimpanzee (a scientific fact) the non-specificity of man (a philosophical statement) is a sophism. This is how one article dedicated to this subject concludes: â?? It is necessaryâ?¦to mistrust pseudo-philosophical conclusions that would emanate, according to some authors, from the works of biologistsâ?¦By deducing from them that man is nothing, an accident, is not â?? a consequence of scientific facts. In the same way, the unique character of a human being is not put up for question by the small genetic distance that separates him from a monkey. The value attributed to scientific information does not result from science â??.91

Limits

 The preceding argumentation, however pertinent, has some limits. In addition to the difficulty related to the current lack of observation of a properly sensitive operation of the zygote (the organ in its agere), the difficulty remains of the subjectâ??s disposition (the organ in its esse). The objection about the great similarity of genomes between a pongid and man, although not conclusive, shows the difficulty of discerning, in the individuated and active organization of the one-cell embryo, the body prepared to receive the act of the spiritual soul. In fact, the distance is always open between the initial potential and the final act and, according to the thesis supported, the supporters of the immediatist or the mediatist position will always work to stress, for the former, the organization that is already there, and for the latter, the actuality that is still missing. This apory may come from an overly unilateral emphasis on the psuchè as the form.

THE PERSON AS A BODY TO BE ORGANIZED BY A SPIRIT

Presentation

 Until now, we have considered the soul as a formal cause: in other words, as the act of the human body. Now, the principle of the living being also performs an efficient function,92 and this is in the extension of the form, as Michel Bastit emphasizes in more general terms: â?? The efficient cause is distinguished from the formal cause in that it determines when it can act or when it acts, but it is confused with it in the sense that the efficiency is only the external extension of the causality of the formal cause already active in the efficient cause â??.93 The question of the animation of the zygote can be taken up contingent not on the dispositions of the subject but of the motor of the embryoâ??s development. In other words, all argumentation has been based until now on the being of the zygote, but it has not taken into consideration its becoming and cause. In my opinion, this argument of a dynamic order confirms in a decisive way the argumentation taken from the soul as a form of the body.

Based on this new perspective, the discussion between immediatists and mediatists can be formulated in another way: the process that leads from the zygote to the formed human being, endowed with visible organs, is, for the former, an accidental becoming, precisely what Aristotle calls a quantitative movement of growth, and, for the latter, a substantial becoming, precisely what Aristotle calls the generation of a new substantial form, in this case a human from, accompanied by the corruption of a form that is substantial and sensitive (or even a dual process of generation-corruption in Aristotle and Thomas). All becoming requires a cause. In the case of the substantial becoming of the living being, this cause must be a univocal agent. What could it be? Stated more simply, any becoming requires a proportioned cause. Anthropogenesis is a becoming. What can the motor cause be that actualizes the subject?

The embarrassment is great for Thomas Aquinas, who follows Aristotle very faithfully. It is worthwhile to follow the ever rigorous formulation that Aquinas gives to this by asking if the seed can cause the animal soul: â?? Any being that generates will generate a being similar to itself. So the being generated must be in act in the cause of its generation. The sensitive soul is not in act in the seed, neither it, nor a part of it: because no part of the sensitive soul is there if not in a certain part of the body. In the seed there is no particle (particular) of the body because no particle of the body comes from the seed or the virtue of the seed. Consequently, the sensitive soul is not caused by the seed â??.94 A simple reading of the objection shows how in the knowledge of the era, the seed cannot contain a particle of the body. It will be necessary to go back to this need for a total, absolute epigenesist, without any pre-formation.

In refusing to accept any creation of the sensitive soul,95 and not being able to base himself on a capacity organically present in the seed, Thomas thus has to refer to a vis activa, an energy or active power that will only be partially within the seed.96 This causality is threefold: the causality inside the seed, its formative power lies in the foamy character of the sperm,97 â?? as its whiteness manifests â?? (albedo). Thomas also speaks about a â?? spirit â?? (intellectus or spiritus) present in the seed,98 but this term should not be misleading. Averroes explains that if the Philosopher uses the term spirit to designate the virtue present in the seed, this should be understood in a figurative sense: what is proper to the spirit is to operate through an organ; and the seed is rightly devoid of this.99 But this internal causality acts in fact by delegation: â?? The active virtue that is in the seed, derived from the very soul of the generator, is a kind of motion (motio) of the generatorâ??s own soul â??. More precisely, the seed is an instrument agent moved by a principal agent which is the soul of the generator, in this case, the father. The formative power of the soul, â?? because it is based like its own subject on the spirit that the seed is fit to contain, because it is something foamy, it brings about the formation of the body in that it acts through the power of the fatherâ??s soul, to whom generation is attributed as its principal agent, and through that of the soul of what is conceived, even once the soul is in him â??.100 Lastly, Thomas adds a third cause, following Aristotle: the sun. In fact, we have seen that through its heat the seed can generate. All heat comes from the heavenly bodies as its first cause. Hence Aristotleâ??s famous formula: â?? What generates man is man plus the sun â??.101

Therefore, there is a triple cause concurring in the emergence of the sensible soul and these causes are conjugated according to the dual hierarchy of instrumental cause-principal cause, univocal cause-equivocal cause: a) the instrumental agent, which is the seed; b) the principal agent, which is the fatherâ??s generative soul and moves as the univocal cause; c) the equivocal agent, which is the sun.102

So it is understandable that since the vis formativa is only instrumental, it asks for all its energy from much more powerful causes: the soul of the begetter and the celestial bodies. But what the seed gains in power it loses in proximity and immanence. Can philosophy stay with a vision of this kind if it allows itself to be enlightened by the new understanding of the beginning of the animated being offered by the biological sciences?

By now, St. Thomasâ?? mysterious vis formativa has been identified with the amazing capacity present in the zygote attested to by biology. This is certain in the chromosomes, but it has also been perceived better and better in the histones, the cytoplasm and so in the whole zygote as it enters into progressive interaction with the environment. While Aristotle and later Saint Thomas needed â?? the vertu of the human act of generation â??, to use Maritainâ??s words, the biological sciences have made immanent the process of development. The philosophy of the living being cannot ignore this greater contribution, which cannot be deduced from common notions and is absolutely certain, regardless of what may come from different knowledge: every animated being is a cell or composed of cells. Every cell contains a genome that brings the building program of the whole organism and the ordering of the agents to carry it out. Therefore, we know that however little it may be, the zygote contains in its heart, that is, in the nucleus, the whole of what it will become. This new knowledge has to be assessed, which is probably the most decisive information from the biological sciences and assuredly the most undreamed of information for the ancients and those of the middle ages. In philosophical terms, the biological sciences have made the ontogenesis of the living being totally immanent. Aristotle understood that the originality of the living being consisted in its self-motion; but this was intended for his otherwise complete being (the Stagirite makes growth one of the three operations of the living being), at least for his being that already had visible functional organs. But embryology and genetics make this autonomy and thus the immanent ability of self-organization go back to the origin and so self-motion includes the whole of becoming. Therefore, it is no longer necessary to have recourse to these â?? crutches â??, these transitive, exterior principles that are the generative act and the sky. The vis informativa has been identified: it is made up by the genome. Any explanation provided by Aristotle and Thomas that took away from the zygoteâ??s own spontaneity and immanent activity must now be given back to it.

It can be said, moreover, that today the process has been explained of the univocal cause exercised by the living being: the efficient and material mechanism â?? which, for Aristotle, resulted from the observation that like generates like â?? has been clarified by genetics. Parental action has no need to continue in the seed through a mechanism that deprives the zygote of its efficacy.103 As long as the presence of the genome and its transmission through the gametes was unknown (and unknowable without instrumental mediation), the hypothesis of a continued action of the generative act, albeit transitive and at a distance, proved to be coherent. The knowledge acquired from biology has made this activity obsolete: the parentsâ?? efficient action stops on the threshold of fertilization. In the same way, a zygote is no longer an instrument moved by the principal agent, which is the parental soul. The most important fact, writes Elio Sgreccia regarding the zygote and the emergence of a new human being, â?? is that this new program is not inert, nor is it executed with the help of the maternal physiological organs that use the program in the same way that an architect uses the project as a passive model; this has to do with a new project that builds itself and of which it is the principal craftsman. Although the information systems of maternal origin that had brought the ovum to maturation remain active for a certain time, from the first moment of fertilization, the control systems of the zygote enter into action and take control completely even well before implantation â??.104 To state this in another style â?? which does not fail to be symbolic: in giving â?? in abandoning to the gametes the secret of life, the parents offered all the essentials to the new being and granted it, in complete confidence, the greatest possible autonomy. By detaching themselves now from any direct and essential participation in the biogenesis, the parents offer the newly conceived, on the part of the mother, a warm and intimate reception that is enveloping and nourishing, and, on the fatherâ??s side, in a more mediatist way, the external but very real protection that is still a form of love.

To go back to a more ontological style, in the debated issue De anima, Thomas takes up again the Aristotelian definition of the soul: the soul is actus corporis organici physici and adds quia anima facit ipsum esse corpus organicum: 105 â?? The soul is the act of a physical, organized body because the soul makes this body organized â??. So in this way the soul is not only the term, but also the principle of organization. In other words, the soul as the formal cause has for its subject the organized body; but as the efficient cause, it has for its matter the body to be organized.

Limits

 This response is not sufficient. We have seen that the classic concept of instrument does not take into sufficient consideration the specificity of the genomeâ??s action. Moreover, some, not without apprehension, will see the manes of Hans Drieschâ??s vitalism rise up again in this approach and they will fear a circular logic.106 Furthermore, the chromosomal DNA plays an essential role in the development of the human being from conception. But once again it is necessary to situate its role: it is the privileged instrument of development but it is not development. It is the material support for information; it is not genetic information (systematized in the famous code that is thus falsely iden- tified with DNA) or much less the information that is the soul, the principle of being and operation. Also, the above argumentation implicitly identifies the genome and the zygote and isolates it abstractly from the cytoplasm. The fertilized cell constitutes a whole and it is the totality that is living. Just to give a very recent example, an Anglo-American team has supposedly just demonstrated that the spermatozoid, far from giving the oocyte only its chromosomes, also transfers a series of DNA messengers, six of which have been identified.107

Lastly, genome and phenotype (this notion itself has taken on many meanings, according to the level of organization considered: cellular, tissue, organic, individual) can be considered in a relation of potentiality to actuality. But they also constitute two levels of organization and thus of actuation. Now, this difference is never thought of as such. Doesnâ??t the observation of this unimaginable thing call for a specific reflection, or doesnâ??t it even manifest an intrinsic limit to the application of the pair act-potential in understanding the structure of the living being, and so isnâ??t this conducive to a new study? A last approach, which is not exclusive but complementary to the preceding ones, will hopefully make it possible to revoke these apories.

THE PERSON AS AN ORGANIZING CENTER

Presentation

 Let us make a backward zoom and consider not only the relation between the genotype and the phenotype, but also the relation of the zygote in its totality to the multicell embryo that it will become, until it becomes a complete adult body. For the supporters of mediatist information, only a body endowed with functional macroscopic organs is fit to receive a spiritual form. Here a dual problem, exegetic and doctrinal, is raised.

First the exegetic problem: the question raised is double. Aristotle requires a living, animated body to be organic, that is, organized. For the Greek philosopher, this epithet is identified in the presence of organs, macroscopic organs that are sensibly identifiable and individually isolable. This dual identification was understood from the time of the Greeks down to the Middle Ages and still in the Renaissance. But the knowledge acquired from the different biological sciences compels an in-depth revision from at least two viewpoints: on the one hand, the organic structure as physiological activity begins well before the eyes can perceive it. We have dealt with this point above. On the other hand, the functional activities of the living being are not only related to the organs but to ubiquitous systems (think of the immune, nervous, hormonal, vascular systems). Therefore, it is ambiguous to continue to identify organic with endowed with organs at least as long as organ is too strictly defined as an isolated and macroscopic principle of action. Moreover, it has been demonstrated that organic can be taken in another sense that is no longer passive but active: organizer. The body would then be both already organized and still to be organized. Therefore, the soul is no longer present at the end of the process (as the formal cause), but also, in a necessary way, at the beginning (as the efficient cause of operations but also of growth).

Next the doctrinal problem: to consider the relation existing between the zygote and the embryo, reference can be made first to the resources of traditional metaphysics. Based on factual information from common sense or science, the supporters of immediate animation and differed animation will interpret them in their own way, giving value to one aspect or another: a) in terms of intrinsic cause, the immediatists will stress actuality more and the mediatists potentiality; b) in terms of efficient cause, the former will refer to the notion of immanent becoming and principal cause, and the latter to transitive becoming (doing) and the ability to produce organs.

Without denying the validity of the preceding categories and their pertinence in clarifying the question of the identity of the zygote, we could ask if it might not be useful to have recourse to phenomenology.108 I do not mean post-metaphysical phenomenology but phenomenology closely joined to metaphysics.109 To state it in an overly brief, even caricatural way, phenome- nology in this sense constitutes one approach to physical phenomena (a fortiori of the reflexive subject), considered in their immanence, given to themselves, in order to explore their resources and see how they exceed themselves, leading to a finished intrinsic foundation that is not reduced at all to a mechanical cause or even an opening where transcendence is played out.110 Since a development of this kind is still largely unexplored, it does not or would not involve a kind of â?? metaphysics to the second power â??, as Blondel says, but a â?? phenomenology to the second power â??.

In the framework of this phenomenology to the second power (and here of the philosophy of nature), I would refer to the distinction between essence and emergence as elaborated by Hans Urs Von Balthasar,111 who far from leaving it in a solely phenomenal perspective, imbues it with metaphysics.112

And I would put forth the following hypothesis: the genome is to the phenotype and the zygote is to the formed organism what essence is to appearance. 113 Let us develop this dual point: the genome constitutes the essence, in the phenomenological meaning of the term, of the living being. In fact, the phe- notypic, morphological organization expresses what is hidden but actually present. Now, the difference, which is not static, between the essence and the more dynamic appearance, between the secret, even mysterious essence and the figure (Gestalt),114 unveiled in the manifestation, pertain to the essence of a one, same event of development.115 Moreover, the objections have rightly stressed the active role of the genome: it constitutes an agent which, like an architect, directs the material transformations and enables the molecules present in the cytoplasm to get organized into a structured and functional totality. Lastly, the genome constitutes an active center. As the Bioethical Center of the University of Milan notes with regard to the zygote: â?? The biological center or coordinating structure (the italics are mine) of this new unit are the new genome (italics in the text) with which the one-cell embryo is endowed â??.116 It will be noted that the text speaks about a â?? center â?? and not a coordinated but â?? coordinating â?? center, thus stressing the efficient role. Furthermore, in the eukaryotes cells, the macromolecule of DNA is situated in a place called the â?? nucleus â??. In the beginning (1530), this term designated the hard part of a fruit, then later the compact part in the center of a natural or artificial element, and afterwards it progressively expanded to the whole area of the natural sciences (astronomy, geology, medicine, biology, electricity, physics, meteorology), human sciences (psychoanalysis, linguistics), and even to technologies (in the fifteenth century the central axe of a staircase; in the seventeenth century, the full part of a spring).117 Lastly, in a figurative sense, nucleus designates â?? a small group of persons â?? â?? that has given rise to a larger group â?? (1794) or carries out â?? an activity in a hostile environment â?? (1844). By analogical extension, this nucleus means the center, secret place and active source, attesting to the ubiquitous presence of that figurative logic whereby the essence of a being is revealed through the mediation of its appearance.

What is true of the relations between genotype and phenotype is also true of relations between the zygote and the embryo in ontogenesis. The zygote appears to be the active center from which everything comes, with order and efficacy. The interior-exterior distinction ceases to be just symbolic or spatial and becomes ontological. Angelo Serra also comes to this conclusion: â?? The newly conceivedâ?¦is a totally human, developing individual which, in an autonomous way, moment after moment, and with no discontinuity, builds its own form by carrying out, through an intrinsic activity, a plan projected and programmed in its own genome â??.118

In a view of this kind, the totality is sealed (in the first act, not in potentiality) in this unique fragment, which is the heart, the center. This constitutes at the same time the hidden essence, the source of every manifestation and the cause of all dynamism. But it is the soul that moves the body. Consequently, a phenomenological perspective concludes with the presence, both motor and manifestative, of the intellective soul at the heart of the zygote.119

Confirmations

 This hypothesis finds eloquent confirmation in scientific, especially embryological data. In fact, the departure point of this discipline is the following problem: â?? Every one of us began his/her life in the form of a cell, the egg â??, writes Nicole Le Douarin. â?? In this case, for the human species, a small corpuscle of living matter 100 µm in diameter. When we linger over this idea, it arouses incredulity and questions â?? the Greeks would have said, admiration and astonishment. From this comes the fontal question of embryology: â?? How can it be that from this one, isolated cell the constituents of the body of an adult spring up, made up of many billions of harmoniously ordained cells to form organs as different and complex as the brain, the members, the eyes or the face? â??120 How can it be stated better that the zygote is the foundational cell, the heart from which the whole living being comes? The biology of development has progressively shown that life has come to the cells not in a kind of continuous growth, but starting from organizational centers, sources of induction, that spring up in a discreet way and act only once. The first of these was discovered by the biologist Hans Spemann121 (who took up the experiments on regulation done by Hans Driesch). But experimental studies have established that Spemannâ??s organizer is preceded upstream by an even more primordial center, the one discovered by the Dutch embryologist Pieter D. Nieuwkoop that now bears his name.122 Furthermore, â?? it has now been established that Nieuwkoopâ??s center is put in place at fertilization .123

This hypothesis is not as far from Aristotleâ??s vision as it may seem. In fact, for the Stagirite, the heart is a principle of the living being. It is first chronologically: â?? The heart is the first part that is differentiated and it exists in act â??124 and ontologically. 125 While the first principle (like the seed) contains the whole living being only in potentiality in the embryo, where in a certain way all the organs are found in potentiality â??,126 this principle is actualized, and, for this reason, individualized in this very first organ which is the heart; moreover, it contains the principle of growth.127 So for Aristotle the heart is the equivalent of what will later be among embryologists the principle of organization. Rodolphe Kempf also comes to this conclusion in an article comparing Spemann to Aristotle on this point. He states that it is authorized to see in Spemannâ??s organizer center the contemporary analogy of the heart in Aristotleâ??s theory. As he explains: â?? The philosopher sees his major ideas confirmed by present- day science: animal morphogenesis uses a center because an animal is fundamentally a centered individual â??.128 This organizer center is the instrumental cause, under the motion of the spiritual soul, of the construction and manifestation of the totality.

Therefore, a dual phenomenal stratification should be affirmed (and distinguished). According to the first visible reality (here the living organized body, but already the structure of the zygote), expresses, reveals an invisible reality (here the spirit that animates). This more classic perspective129 is not the one developed here, even if it is implicitly present. The second stratification is internal to the body: the somatic structure itself verifies this demonstrative logic and, once again, on different levels: the nucleus unfolds in the organization of the cell; the initial and initiating cell, the zygote, is the center and source of the whole architecture of the body. Lastly, when the organism has already unfolded and opened up, it gives itself some partial centers of organization (Nieuwkoopâ??s). What is real thus seems to obey a logic of phenomenal construction and this follows a process of stacking into Russian dolls, which the fractals attempt to systematize. Be that as it may, a living being is constituted from a nodal or nuclear or cordial reality130 that presents the quadruple characteristic of being geographic because it is central, historic because it is original, dynamic because it is fontal, and phenomenologicalontological become it is the mysterious essence that is expressed without ever being exhausted, in the organic totality.131 Now we have just seen that meta-physical phenomenology makes the interior-exterior/essence-figure distinction significant. It thus gives value to the morphological capacity of the embryo and makes the membrane much more than an exterior frontier: it is the exterior manifestation that a living being gives itself based on its innermost depths.132

SOME RESPONSES TO THE ARGUMENTS

Homozygote twins

 The argument taken from homozygote twins confuses individuality and indivisibility: an individual is characterized by its individuality (in act), not by its indivisibility (in potentiality). Moreover, the emergence of monozygote twins is depicted as a split of the embryo in two. Now, more often than not it involves the detachment of one blastomere from many others. So it is not one embryo that becomes two, but one that comes away from the other. If we absolutely want an image, we might refer to the rich biblical symbol of Eveâ??s birth from a part of Adam (the side, a metaphor of the heart, is a significant fragment of the totality). Vincent Bourguet makes this correction: â?? Rather than saying that one becomes two, it should be said that the initial zygote remains after the split into one of the two twins â??.133

Furthermore, two realities are misleading. The first is the term twin itself. It implies the perfect equality or even convertibility between the two embryos, while it has more to do with a process of filiation (asexual but not parthenogenetic). This term, which came from the morphological resemblance, erroneously ebbed back to the origin. The second reality consists in the small time period of time between the emergence of the first and the second twins, which tends to be overlooked compared to the scale of a lifetime. And yet, this difference is considerable if it is considered not on the chronological but on the ontological level: one of the beings is not the origin, but at the origin â?? corporal â?? of the other. One indication points this out: if it takes several days to go from one cell to 64 cells, imagine what it would be in an adultâ?¦

Lastly, Philippe Caspar has demonstrated, in my opinion in a definitive way, one of the principle historical origins of the conceptual confusion between individuality and indivisibility: Leibnizâ??s metaphysics of the monad. Just to take one example, there is a striking connection, which is not only conceptual but verbal, between Leibnizâ??s theory and that of Jean-François Malherbe and Edouard Boné: â?? By individual I mean a being that destroys its own separation and whose fusion with another being is impossible â??.134 In fact, Leibniz blocked the concepts of monadic individual and indivisibility: according to the principle of indiscernibles, two strictly identical individuals could not exist. Now, two homozygote twins are genetically identical so they cannot exist: one substance cannot be divided into two, nor can one be made out of two â??.135

Totipotent cells

 Totipotentiality can be interpreted in two opposite ways: as an undifferentiated indetermination, as the objection does, or as a reserve put at the service of the good of the embryo. This second line of interpretation is what proves to be true, as shown by the famous embryologist A. Pedersen: the development process requires the embryo, at early stages, to be able to accept modifications in the program and impose them on the cells that are already differentiated in the interest of the whole that is being formed.136 Moreover, the recent discovery of the presence of pluripotent cells in the adult (what are called stem cells) is in favor of the second hypothesis. They serve to repair the sick organs. For example, a Swedish team has shown that neural stem cells were able to form normal hearts.137

In the light of this objection, which is almost as recurrent as that of the homozygote twins, I wonder if we should not ask ourselves in a more general way and from a metaphysical viewpoint about the concept of potentiality and actuality inferred by the new information introduced by the biological sciences. In a word, wouldnâ??t it be necessary to go from the act conceived of as a reduction in potentiality, to the act in the sense of a power over the potentiality or a power beneath it? Therefore, the indetermination of the totipotent cells constitutes a potentiality over which the soul can exercise its empire, its act: the act is not an imperfection waiting for determination, but a perfection, a source of determination, a power beneath it.138

The embryo as a being with relations and speech

 The argument comes close to the sophism of the red fish: remove the water from the container and the fish will die; put the water back, but it will not necessarily come back to life. So the brain is the condition of thought, not its cause. As the great biologist Pierre-Paul Grassé also noted: â?? It was pre- sumed that a fÅ?tus was not a man until it acquired its nervous system. It is none of this. This acquisition, which is made at the very beginning of embryonic life, does not change the nature of the being that is already endowed with all the potentialities of its species. It does not add anything to it, not even conscience, which will only appear after birth â??.139

More fundamentally, those who object base themselves on the non-significant character of human life; they have postulated that the only source of meaning is the spirit.140 A concept of this kind dates back to the divorce between nature and spirit characteristic of the Galilean-Cartesian heritage.

Furthermore, those who object reduce zygote-mother communication too much to an exchange of nourishment and information. The environment and the container are not extrinsic to the content, in this case the living being, except in a geometric reduction of the place to space. The mother gives more to the zygote than nourishment and information: the warm, loving protection of her body, the protective secret hiding place, the communication of her intimate emotions, starting with her joyful acceptance of motherhood, etc. Far from being just physical and physiological, this primordial envelopment plays a sensible and even a really spiritual function since it concerns both the body and the three degrees of life.141

Without going into a detailed evaluation of the approach proposed by Ricoeur to ipseity, we could ask if in wanting to exorcize the ontologizing or even biologizing risks of the identity-idem, he does not fall into the symmetric error of devaluating corporal continuity too much, the spiritual origin of every human being, and of not seeing how much narration presupposes and appropriates these primordial facts? Behind this error, moreover, there is the post-Cartesian dichotomy of nature and freedom, and a desperate lack of metaphysical reflection.142

Recognition by others

 It is essential to the humanization of the new being for it to be recognized by its parents, especially its mother. When a baby is not spoken to or given any sign of love, an affective deprivation is produced that can lead to death.143 The objection thus indicates a truth that will never be stressed enough and which can be summarized in a drastic formula: only some children are adopted; all children should be adopted through an act of parental recognition.144

This recognition, however, supposes meaning; it does not constitute it. It is not because the parents accept the embryo that it is a man, but because it is a man they raise the question of accepting it. This is what the founder of maternology states in another way: â??A child does not come from thought unless it abandons itself to the flesh, if it becomes flesh. Any mental or genetic manipulation turns against the flesh; any opening of the spirit to the flesh leads it back to the source where life is made. And life comes back to the flesh. Life does not come out of a laboratory; there would only be some life, not a living being. Life comes back to the flesh even though it has become spirit â?? and the spirit plunges back into its substance which is not thought, but the sensation from which it can think, its immersion in the dream that makes the flesh possible, the union of the flesh â??.145

Lastly, the objection affirms in practice what it denies in theory. No coherent biologist constructs his object or decides about its identity through an act of speech. In his biological practice, René Frydman knows that the human gametes and zygotes present under the eye of his microscope obey specific laws and that if he transgresses them, he will not observe anything and, apart from any ethical evaluation, he will not achieve any fertilization in vitro.

The number of spontaneous abortions

 The argument is erroneous from a scientific viewpoint. The number of spontaneous abortions has been over-evaluated for a long time (like many other authors, Patrick Verspieren speaks about half, without citing his sources). Out of 198 conceptions diagnosed through tests based on HCG, A.J. Wilcox and his team count 155 clinically identifiable pregnancies and 136 brought to term.146 Moreover, we know today that spontaneous miscarriages are not random, arbitrary events. Most early miscarriages are linked to nonviable abnormalities. So the embryo aborted by nature constitutes an organism that is insufficiently fit or even resistant to animation. A polyploidy, for example, makes it unfit for this human identity. It is well-known, says Anne MacLaren, â?? that in our (human) species there is a very high incidence of chromosomal abnormality â??, much more than for any other known animal species, and we do not know why.147

The error is also philosophical. Let us concede that spontaneous abortions are frequent, or even that the causes may not be pathological. However, does their frequency make them natural? This is a property or even an accident, not the essence of the naturalness of a process. A process is considered natural because it is aimed at an accomplishment: the acquisition of a determination, what Aristotle would call a form.148 Spontaneous abortion is by definition the disappearance of a being, thus the privation of a determination. Moreover, it constitutes a failure. The failure occurs by accident: by definition, this is outside the intentional order. But nature is the principle of movement by itself and not by accident.149 Consequently, in all rigor it cannot be stated that a spontaneous abortion is natural.150 Of course, the current use of the term natural has gradually identified it with spontaneous, in which case it would be redundant, pleonastic to describe a spontaneous abortion as natural. But in its full, rigorous meaning, natural means an innermost logic present in physical beings, and the commonly known polysemy of this epithet risks leading to a dangerous shift in meaning. Moreover, this presumably natural behaviour can be used even less as a basis for imitating it.

The need for an organized body

 This argument has been answered at length in the body of the text, so I will not go back to it. I would only add one psychological observation: isnâ??t the blockage between organization and the presence of identifiable organs another offense to the intelligence through methodological monism, that is, through exclusive polarization on one type of approach to what is real? In fact, a zygote can be considered from the genotypic or phenotypic viewpoint regarding its final macroscopic morphology (I did not say completed) or regarding its initial microscopic morphology (I did not say sketched out). It is significant that Aline Lizotte does not adopt or take up the genetic viewpoint, and that at least as an objection, she does not tackle the question of the status of the genomeâ??s organization (on the dual structural and operative plan).151

Vince Bourguet â?? like Philippe Caspar â?? has rightly criticized the undue privilege given to morphological and anatomical criteria. Although he was not able to distinguish the dual morphological (being) and physiological (acting) aspect present in the terms organization and organ and the importance Aristotle gave to the latter, in the name of his definition of nature as the internal principle of operation, Vincent Bourguet rightly stresses the confusion between human and adult: â?? An individual can belong to the human species without having any morphological property of an adultâ??. This â?? is the case of the zygoteâ?¦it is not a potential human being, it is at present a human being with the potential to be an adult â??. Overturning the classic interpretation, the author feels that it is necessary to let oneself be instructed by the case of the living human being as to what individuality is rather than dumping our more general concept of individuality on it: â?? The study of man teaches us that he exists first in the form of one, then of several cells closed in a membraneâ?¦, this seems to us to be the teaching of biology concerning manâ?¦A human being goes through the different orders of reality, from elementary to complex, and to conscience, and it is this ascending trajectory he goes through that defines his individuality â??.152

To cure the intelligence of this unilateralism or, in any case, to favor a dialogue between the two perspectives, isnâ??t it necessary to regain the ability to wonder before the prodigious organization present in the embryo? The philosopher Nicolas Malebranche, in assiduously cultivating the sciences, felt this when he observed the formation of the chicken in the egg: â??Yes, Ari, the egg is the work of an infinite intelligence â??.153 The process of embryonic development, says Lewis Wolpert, â?? is one of the most exciting problems of modern biology â??.154 Moreover, the advances in the biological sciences over the past one hundred fifty years have forbidden us to disconnect our structural and physiological view of the living being from its historical approach (which has nothing historicist about it). History teaches us the decisive importance of the beginning. In the same way, the sciences of the living lead us to wonder at these beginnings that are not only very rich in promise but in actual content: â?? The unity of the origin of all the cells of a metazoan has more importance than their current multiplicity â??, said Georges Canguilhem. â?? The origin of the metazoan is the egg; that unique initial cell that partitioned and divided itself, not some pre-existing cells that would be grouped together â??.155 Doesnâ??t the fact that a living being is not built through agglomeration but interior growth signify the unfathomable riches of the origin?

CONCLUSION

In every era, man has been impressed by the extraordinary development that takes place between fertilization and birth. Today, however, the sciences do not allow us to see this only as a passage from potentiality to actuality. From the starting point, a zygote is already an extraordinarily organized and active being, in other words, a being in act. It is not a potential person, but a person with a potential. Some years ago, a President of the French Republic stated that the twentieth century was the century of biology.156 We hope that the 21st century will be the century of a philosophy of biology capable of accounting for it in a satisfying way.

As a Christian, I will add one word: from the creation of the world, the only real and absolute newness â?? I am speaking about newness in being not in acting â?? is the human being. Ever since God, through his creative Word, made the universe from nothing, but even more from his love, he did not intervene directly, immediately, to create a new being before the emergence of the first man. And he acts, he moves, if I may say this, through every embryo he inserts into the fabric of the universe and humanity. This says something about its importance and its value.