Was den Menschen zum Menschen macht

Peter Singer

4 Min. Lesezeit

🇩🇪 Deutsche Version: Peter Singer

Peter Singer is the most prominent contemporary proponent of the thesis that not all human beings are persons. In the book his position serves as an example of the radical consequences of the empirical-functionalist concept of person and as a warning against the practical forgetfulness of the person.

Key Contribution

Singer advocates an empirical-functionalist concept of person: personhood is tied to empirically ascertainable capacities — above all rationality, self-consciousness, and the capacity to have future-directed interests. From this follows the provocative thesis: not all human beings are persons. According to Singer, embryos, newborns, and human beings with severe dementia or irreversible loss of consciousness are not persons, because they do not (or no longer) actually exercise the required capacities. Conversely, higher animals could be persons if they possess the corresponding capacities (cf. Bexten 2017, pp. 90–100).

Central Ideas in the Book

The Separation of Human Being and Person

Singer draws the logical consequence of Locke’s splitting of “human being” and “person”: if person is a functional concept, then there are human beings who are not persons — and non-human beings who could be persons. Dignity and the protection of life then depend not on being human but on the actual capacity for rational self-reflection.

The Inversion of agere sequitur esse

Singer’s position is the complete inversion of the Thomistic principle agere sequitur esse: it is not being that determines acting, but actual acting (the empirically ascertainable function) that determines whether someone counts as a person. Personhood becomes person-behavior — whoever does not behave personally is no person.

Counter-Argument: Active Potency

The potentiality argument — in its Aristotelian-Thomistic sharpening by Günther Pöltner — strikes Singer’s position at the ontological level: whoever ties personhood to actual rationality confuses active potency with passive possibility. The rational nature of the embryo is prote energeia (first actuality), which unfolds rather than being first acquired.

The Performative Contradiction

The book project’s most radical answer to Singer is the performative contradiction — Bexten’s own further development (2026), following Karl-Otto Apel’s transcendental pragmatics, which closes a systematic gap in Spaemann and in this form is not contained in the 2017 dissertation. Whoever argues as a philosopher, advances reasons, refutes objections, and raises a claim to truth performs in these very acts precisely what he theoretically wants to restrict to a narrow subset of human beings: personhood as rational, truth-apt, responsible being-over-against. Singer’s position refutes itself not in the content of its statements but in the performance of asserting. To this are added the exclusion objection — embryos, newborns, and severely demented human beings fall outside Singer’s circle of persons — and the diachronic identity objection, which shows that Singer’s reduction of personhood to psychological continuity must already presuppose the very personal identity it is supposed to ground. Both objections are already systematically unfolded in the 2017 dissertation.

Theoretical and Practical Forgetfulness of the Person

Spaemann sees in Singer’s position the unity of theoretical and practical forgetfulness of the person: the false theory (person = function) leads to the false practice (no protection for “non-persons”). The book shows: Singer’s argumentation rests on the confusion of personhood (First Dimension) and person-behavior (Second Dimension).

Place in the Book

Singer is analyzed as a counter-position in the chapters What Is a Person? (German) and What Happens When We Forget Who the Human Being Is? (German). His argumentation is measured against Boethius’s insight that person is to be sought not in the realm of accidents but in that of substance.

Sources: Bexten 2017, pp. 90–100 (Singer’s empirical-functionalist concept of person and the consequence of separating human being and person).

Further sources:

  • Practical Ethics (1979/1993). Cambridge University Press (personhood tied to rationality and self-consciousness — not all human beings are persons)
  • Rethinking Life and Death (1994). Melbourne: Text Publishing (radical consequences of the functionalist concept of person for the protection of life and bioethics)

See also

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