Contrary to what is commonly supposed, human beings and other living entities do not begin to exist only at their birth. – This is already supported by the fact that individual creatures belonging to the majority of species are indeed not “born” but rather crawl or slither out of eggs or larvae. And those creatures which are indeed “born” in the strict sense of the term begin to exist in utero, before they are actually born. Thus, whereas the end of the existence of a living being is designated by the term “death”, language lacks a symmetrical notion to designate the beginning of such a being:
Since “birth” designates the emergence of an already-living being from the maternal womb but not the actual beginning of the life of the being in question, people asked about their age regularly leave illegitimately out of account those months which they spent, alive, in utero. For lack of a better notion, then, let “beginning of life” designate the beginning of the existence of a new living entity.
In order to be able to answer the question of just what it is that distinguishes our beginning of life/beginning of existence, we must first establish what we essentially are, or what we are identical with. Mostly it is held that we are identical with our functioning organism and that we began to live shortly after conception when our organism began to exist/to function. With the following contention we take up a divergent viewpoint to this one: Our organism was begotten, but our organism constitutes us. More precisely, it was the brain of our already-functioning organism which constituted us, as soon as its functionality was sufficiently complex to generate simple consciousness (sensations). We maintain that we are not identical with our functioning organism but rather with the consciousness generated by our brain. Consequently, we can state our position more precisely as: Our organism was begotten, but our brain generates us. This proposition contains the interesting implication that we would never have begun to live – and would never have had to die – if the organism had been destroyed before it created the brain which later generated the consciousness that we essentially are.
The question as to the point in time at which human brains begin to generate a rudimentary consciousness can hardly be answered with any precision. If one assumes that in order for consciousness to exist at least certain primitive neural structures must be present, we can say that an embryo less than eight weeks old will certainly have no consciousness. This being the case, such an embryo is, indeed, a functioning human organism but still no living human being. If this hypothesis holds, then the many spontaneous miscarriages which occur constitute no “loss of human life” but rather only the loss of functioning human organisms; similarly, abortions carried out before the embryo has attained an – estimated – age of eight weeks are not to be classed as the murder of human beings but rather only as the destruction of functioning human organisms. In all the cases known to us the beginning of the life of an entity takes the form of a transition from organism to living being.
In support of our thesis of a difference in principle between organisms and living beings we offer the following considerations: (1) If we ask ourselves what we essentially are, it is possible for us to strip away from ourselves, in thought, all our body parts and finally even our entire organism without our thereby ceasing to exist; but the brain that generates our consciousness cannot possibly be “thought away”; were we to replace the brain in our head with some other functioning and consciousness-generating brain, then someone else would exist there in our place. (2) For some decades now this thesis has actually found some practical application in the form of brain-related criteria for declaring an individual dead. In hospitals a human being is declared dead when it is established that the brain of the individual in question has irreversibly ceased to function, even if the body of the patient, through artificially-assisted respiration, continues to do so. (3) There exists, then, a decision-procedure based on firm criteria for the question of whether, when faced with a functioning organism, we are dealing with a living being or whether this is only the case where we find ourselves faced with an entity possessed of consciousness: Would we deny to an electronic system of which it had been unequivocally established that it possesses awareness or even self-awareness the title of “living being” simply because it cannot count also as a functioning organism? Or would we rather say that we do indeed have to do here with a living being because the being in question has sensations, emotions or even reason?
We must hope that each of us would indeed feel it to be right to categorize an electronic system possessed of awareness as a living being and an electronic system possessed of self-awareness as a person. Because it is on ontological categorization that ethical characterization depends. An electronic system susceptible of feeling pain to which one were unwilling to ascribe the status of a living being would be far easier to subject to mistreatment than would be one considered as a living being.
Against the background of all that has just been said it seems to us that there applies, as regards the onto-ethics of the beginning of a life, the following truth: the beginning of the life of a human being is not something that “concerns” the human being in question; it is rather the precondition for anything’s being such as to “concern” a human being at all.
 The state of having been born, says John Stuart Mill in his System of Deductive and Inductive Logic, is a separable accident of the human species. This is especially the case inasmuch as foetuses are unborn human beings. Existence, on the other hand, is an inseparable attribute of every human being – for which reason it is onto-logically impossible to carry a human being over into existence. (Mill, System of Deductive and Inductive Logic)
 For further details see: Akerma, Lebensende und Lebensbeginn (2006).