But what do we mean when we speak about 'someone', giving him the name of a person and attributing to him a particular status that distinguishes him from 'something'? This volume, although rather unhomogenous because it alternates very complex pages with original insights and convincing arguments, engages in a rich phenomenology of the human, and takes into consideration Hume's law, intentionality, freedom (and the ability to distance oneself from one's own desires), and temporality; it also relaunches the subject of the soul, and explores consciousness, interpersonal recognition, the factors of morality of actions, moral absolutes, and the practices of promises and forgiveness.
Here we can only focus in on the central subject of the volume, that is to say the criticism of empiricist anthropology, according to which a subject who belongs to the human species is a person only when he manifests possession of certain requisites such as self-consciousness or memory: thus foetuses, the retarded, and individuals in a state of coma or in a vegetative state, cannot be included in the category of persons and thus not only abortion and euthanasia are practices that are morally licit, but also, in the view of bioethicists such as Singer and Engelhardt, the killing of newly born children and the mentally retarded (unless these killings bear upon the happiness of subjects who are persons, such as, for example, their relatives).
Spaemann takes from Boethius the well known definition of a person as substance of a rational nature: a person is not that substance that exercises 'underway' rational activities but that substance that has 'in potential' the capacity to exercise rational activities (cognitive but also volitive acts, aesthetic acts, amorous acts, etc.). This conception is defended in particular in the last chapter of Persone, in which Spaemann expounds six incisive arguments. Two of these will be examined here.
For the examples of a species of things it is inconsequential that other things of that species exist: for the existence of a chair, that other chairs exist is inconsequential. However for living things, and in particular for the person, this is not inconsequential because the existence of other persons is constitutive for each individual person: I would not exist if there had not been before me other persons with whom I am in a relationship of kinship and parenthood. In other terms, the biological fact of kinship is constitutive of the person, that is to say the relationship of kinship institutes the personality of the person, thus those who belong to the biological species homo sapiens sapiens are for that very reason already in an interpersonal situation.
The activities that only in their actual emergence determine, according to the empiricists, the person, only emerge when the mother, of somebody on her behalf, treats a baby already as a person and not as a mere living being. The baby learns to speak not simply because he feels somebody speak (attempts have been made without success to teach babies to speak using videocassettes) but because the mother addresses him and treats him already as a person. If the mother treats the baby as though he is to become a person, believing, however, that he is not yet a person, the baby does not manage to express the activities of the person. There is not, therefore, some move from something to somebody; that is to say, the baby from the very outset is somebody.
Therefore, 'there can and must be a sole criterion for personality: biological membership of the human race. For this reason, the beginning and the end of the existence of a person cannot be separated from the beginning and the end of human lifeThe being of the person is the life of a man' (p. 241). So, overall: vivere viventibus esse (Aristotle already made the point) and the flowering of the person is love: 'we only live fully when we love' (p. 75).