The diachronic identity objection is directed against any theory that attempts to explain personal identity through psychological continuity or through a bundle of changing experiences. It runs as follows: if the self is nothing more than a sequence of interconnected states of consciousness, then it remains inexplicable why we address the person yesterday, today, and tomorrow as the same person — even though her states may have changed completely.
David Hume sharpened the position: when I look into myself, I encounter only individual impressions and ideas, never a continuous self. According to Hume, the self is a bundle of perceptions. Derek Parfit developed this position further and claimed that personal identity is ultimately not what matters — what matters is the psychological continuity between temporally successive person-stages. Identity becomes a matter of degree.
The objection replies: a bundle of experiences cannot itself explain why it is my bundle. For a sequence of experiences to come into view as a diachronic unity at all, there must already be an identical subject to which these experiences are ascribed. Psychological continuity presupposes personal identity and cannot constitute it. Whoever says today “I remember my self of yesterday” makes a statement of identity that goes far beyond the mere similarity of two layers of experience.
Bexten formulates this objection precisely against the memory theory in his dissertation:
This attempted explanation, by which the non-existence of an underlying being of the person is meant to be compensated for, appears to be inconsistent, since a memory always essentially requires an underlying being (subject) that remembers something. The memory of something therefore cannot be unity-constituting, cannot be person-constitutive, since every memory already and essentially presupposes the person who is able to remember something, because she possesses identity, a unified being, and thus personal life.
— Bexten 2017, pp. 106f.
Philosophically, behind the objection stands the classical distinction between substance and accident. The subject remains the same while its states change. Without such a substantial subject, talk of change would lose its meaning — for change presupposes that something changes, not merely that states succeed one another.
The substance-ontological concept of person can account for diachronic identity, because it determines the person as substance — as a unified entity bearing through time, possessed of a rational nature.
In the argument map of the concept of person: The objection constitutes the systematic ground for refuting Hume’s bundle theory and Parfit’s thesis of psychological continuity — both positions are marked in the map with a red refuted edge.
Ontological placement: Superordinate concept: Objection; directed against: Empirical-Functionalist Concept of Person
Chapter assignment: Chapter 3: What Is a Person?
Sources: Generated by querying the Personhood ontology.
Further sources:
- Hume, David: A Treatise of Human Nature, Book I, Part IV, Section VI (Of Personal Identity).
- Parfit, Derek (1984): Reasons and Persons. Oxford: Clarendon Press, Part III.
- Spaemann, Robert: Persons: The Difference between ‘Someone’ and ‘Something’. Translated by Oliver O’Donovan. Oxford: Oxford University Press, 2006, chapter 8 (Time).
See also
Identity, Substance, Substance-Ontological Concept of Person, Empirical-Functionalist Concept of Person, Exclusion Objection, Performative Contradiction, David Hume, Derek Parfit, Robert Spaemann, Chapter 3: Concept of Person