A theoretical position that denies the ontological autonomy of the human being and grasps it as merely a phase or variant of intelligent systems. Posthumanism is a form of theoretical oblivion of the person — it fails to recognize the dignity of the person not through fantasies of optimization (that is what transhumanism does), but by denying that there is any specifically human nature at all.
Posthumanism and transhumanism — a necessary distinction
Transhumanism and posthumanism are often named in one breath, yet they are structurally different:
- Transhumanism is a future-directed program: it holds human nature to be deficient and seeks to overcome it technologically.
- Posthumanism is a descriptive anthropology: it denies that there is a human nature as an ontologically autonomous magnitude at all. For posthumanism, the human is only a contingent phase in the transition to other forms of embodied or disembodied intelligence.
Both positions meet in their rejection of the classical-personalist image of the human, but approach it from different sides. Transhumanism still accepts that the human is something (only in need of improvement); posthumanism denies that the human is something determinate.
Why posthumanism fails to recognize personhood
The personal-ontological answer to posthumanism runs: there is a human nature — not as a biological species property, but as the First Actuality (prote energeia) of a subsistent being with a rational nature. This is the Thomistic and Boethian formula of the person: naturae rationabilis individua substantia.
Posthumanism undermines this formula in two ways:
- By dissolving the substance (individua substantia) into a process- or relation-description — the human is “in becoming,” “in transition,” “in relation.” The person thereby loses its ontological bearer.
- By declaring the rational nature (naturae rationabilis) contingent or interchangeable — other bearers could have the same or a better rationality.
Both lead to the dignity of the human being no longer being grounded in its being, but in properties that it could also lose or that other beings might likewise exhibit.
Posthumanism and artificial intelligence
Artificial intelligence is the concrete occasion at which the posthumanist position becomes virulent. When machines display linguistic capacity, pattern recognition, planning and learning processes, the question seems warranted: is the human merely a particular implementation of cognitive functions — and therefore replaceable by other implementations?
The personal ontology objects. The question is not whether machines can perform human-like functions — this they can increasingly do well. The question is whether function and being are the same. A substance-ontological conception of intelligence distinguishes the capacity (habitus, prote energeia) from the act (enactment, deutera energeia), and both from the bearer of the capacity. A bearer of intelligence without substantial selfhood performs no acts in the first person — it merely produces a surface that looks like acts.
Magisterial assessment
The dignity of the human being is consistently described in the Catholic magisterium as an inalienable, ontological, and precisely not a functional property. Three documents gather this position:
- Dignitas Infinita (Dicastery for the Doctrine of the Faith, 2 April 2024, published 8 April 2024) differentiates human dignity into four dimensions — ontological, moral, social, and existential dignity — with the ontological forming the irreducible foundation.
- Antiqua et Nova (Dicasteries for the Doctrine of the Faith and for Culture and Education, 28 January 2025) identifies the danger not as AI itself, but as the anthropological reductionism that understands the human according to the measure of the machine.
- Magnifica Humanitas (Pope Leo XIV, 25 May 2026) — the first encyclical on safeguarding the human person in the age of artificial intelligence — rejects transhumanism and posthumanism together: transhumanism, because it misconstrues finitude as a deficiency; posthumanism, because it denies the imago Dei structure of the human. “No machine can replace the splendor of human dignity” (no. 15).
Posthumanism as oblivion of the person
Structurally, posthumanism is a theoretical oblivion of the person of the second order: it fails to recognize not a particular person, but denies that there are persons in the substantial sense at all. To this corresponds a thoroughgoing avoidance of the mode of address: where there is no one who would have to be addressed, there is also no one to whom one could do wrong. Precisely this consequence makes posthumanism a morally problematic position — it deprives the Personalist Norm of its addressee.
See also: Transhumanism, Oblivion of the Person, Artificial Intelligence, Personhood, Dignity, Nature
- Chapter 5: Oblivion of the Person (German)
Ontological classification:
- Superordinate class: Theoretical Oblivion of the Person
- violates: Personalist Norm
- related: Transhumanism, Anti-Essentialism
Sources: Generated by querying the Personhood ontology. Bexten 2017 (on the substance-ontological conception of the person as the counter-position).
Further sources:
- Spaemann, Robert (1996): Personen. Versuche über den Unterschied zwischen „etwas” und „jemand”. Stuttgart: Klett-Cotta. (Ontological distinction someone/something against any gradualist or relational dissolution)
- Dignitas Infinita (Dicastery for the Doctrine of the Faith, 2 April 2024, published 8 April 2024): Four-dimensional differentiation of human dignity
- Antiqua et Nova (Dicasteries for the Doctrine of the Faith and for Culture and Education, 28 January 2025): AI as a model of the human vs. AI as a tool
- Magnifica Humanitas (Pope Leo XIV, encyclical, 25 May 2026): First encyclical on safeguarding the human person in the age of artificial intelligence
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