The Limits of the Self in Ontological Materialism: On the Indeterminacy of Exclusive Personal Identity

This paper examines whether a strictly materialist worldview is capable of grounding exclusive personal identity over time. The point of departure is the distinction between qualitative identity and numerical identity, together with the observation that many contemporary debates tacitly assume that one’s own experiencing self continues as exactly the same subject. By means of a copying thought experiment, and by taking into account the continuous material turnover in the human brain, the paper shows that, under materialist assumptions, qualitative duplicability is in principle possible. In such parity scenarios, all functional, causal, and psychological criteria of identity are satisfied multiple times, without yielding any criterion that fixes exclusive numerical identity. The resulting problem is neither epistemic nor technical, but structural: materialism cannot derive exclusive personal identity from material facts alone. The analysis makes explicit the following combination of premises: (i) ontological materialism, (ii) the principled duplicability of materially functional structures, and (iii) the exclusivity of personal continuation. Under these assumptions, exclusive numerical identity cannot be secured by additional data or technical detail, but only by revising the underlying claim or by introducing a non-qualitative supplementary principle (for example, a primitive identity fact). Alternative theories of personal identity are not refuted, but classified as coherent strategies of claim revision that abandon exclusivity. The paper concludes that the issue at stake is not an empirical gap, but a systematic limit of materialist ontologization. Materialism is therefore not challenged as a scientific method, but its claim to fully explain the self as an exclusively identical subject is thereby constrained.