Original presentation
The six-step argument is an original systematic synthesis (Bexten 2026). The building blocks — agere sequitur esse, the exclusion objection, the potentiality argument — derive from the substance-ontological tradition; the six-step structure as a connected argument concerning the beginning of human existence is an original contribution.
When does a human being begin? The answer is clearer than many think: with the fusion of egg and sperm cell. Why this is so can be shown in six steps — they follow the substance-ontological line drawn by Boëthius, Thomas Aquinas and Robert Spaemann, and bring it to bear on the question of the beginning.
1. What someone is and what he does are different things
Every human being thinks, feels, decides and loves. This presupposes that someone is there who does so. Yet the doing does not bring forth the existing. Being precedes acting — agere sequitur esse. Hence no one can cease to be a person merely because he happens not to be thinking, feeling or acting. Sleep, unconsciousness, or the pause between two thoughts are not the extinction of the person.
2. Even one who can no longer do anything remains human
A human being with dementia can no longer think in an ordered way, even though his inner experience, his feelings and moments of clarity remain until the end. A human being after irreversible loss of brain function, kept alive by a heart-lung machine, will never feel again. Both remain persons.
Whoever denies this would have to say: beyond a certain loss of capacities, one ceases to be human. Being human would have to be earned and could be lost — a presumption. This is precisely where Peter Singer’s empirical-functionalist concept of person enters in, together with its refutation by the exclusion objection and the performative contradiction. (Peter Singer)
3. The embryo is human
In the fusion of egg and sperm cell, an independent being of human nature comes into existence, oriented from within toward thinking, freedom and love. The embryo does not become a human being through development — it merely unfolds what it already is. There are no “persons-in-the-making.” The embryo is a someone, not a something. The potentiality argument sharpens this insight conceptually: active potency is the self-unfolding of an already existing substance of rational nature, not the passive possibility of first being made into such a one.
4. Human life is the life of a person
The distinction between biological life and personhood cannot be sustained either in reality or in thought. The biological life of a human being is always the life of a person — the body-soul unity forbids any cut between bios and persona.
5. Every human being possesses inalienable dignity
If a human being is a person from the beginning, he possesses from the beginning a dignity that no one can give or take. It belongs to the ontological essential form of the person, not to some achievement she renders. The human being is a someone, not a something.
6. From this dignity follows the right to life
Every fundamental right is grounded in the dignity of the human being. If dignity exists from conception, then so too does the right to life from that point on — solely on the basis of what the human being is of itself, not on the basis of what it can do or accomplish.
Conclusion
Whoever looks with understanding recognizes: every human being is, from the very beginning, a someone. And has dignity and a right to life — from the very beginning.
In the argument map on the concept of person (German): This argument gathers the substance-ontological line (Boëthius, Thomas, Spaemann, Bexten) on the question of the beginning of life and stands in the map against the empirical-functionalist concept of person (Singer, Locke, Hume, Parfit). It takes up the structural moments of the performative contradiction and the diachronic identity objection and leads them to a normative consequence.
Ontological classification: Superordinate concept: Personhood; connects: Embryo, Dignity, Right, biological life, personal life.
Chapter assignment: Chapter 3: What Is a Person? (German)
Sources: Generated by querying the Personhood ontology.
Further sources:
- Spaemann, Robert (2006): Persons. The Difference between ‘Someone’ and ‘Something’. Translated by Oliver O’Donovan. Oxford: Oxford University Press.
- Thomas Aquinas: Summa Theologiae I, q. 29 (on the person); Quaestiones disputatae de anima (on agere sequitur esse).
- Bexten, Raphael E. (2017): Was ist menschliches Personsein? Der Mensch im Spannungsfeld von Personvergessenheit und unverlierbarer ontologischer Würde (German). Dissertation, Catholic University of Eichstätt-Ingolstadt.
See also
Embryo, Fertilization, Dementia, Irreversible Loss of Brain Function, Dignity, Ontological Dignity, Right, Personhood, Someone, Agere sequitur esse, Body-Soul Unity, Substance-Ontological Concept of Person, Empirical-Functionalist Concept of Person, Potentiality Argument, Performative Contradiction, Diachronic Identity Objection, Robert Spaemann, Raphael Bexten, Chapter 3: Concept of Person (German)