When people say they want immortality, what do they actually mean? A 2025 paper by Anda Zahiu, Nancy S. Jecker, and colleagues introduces the concept of “Person-Span Extension” and asks a provocative question: can AI doppelgangers provide a meaningful form of immortality, even if they lack consciousness?

The Three Aims of Immortality

The researchers argue that the desire for immortality is not monolithic. It decomposes into three distinct aims:

The Experiential Aim: The desire to continue having subjective experiences, to keep feeling and perceiving.

The Legacy Aim: The desire to complete life projects and influence the future, to finish the novel, see the company succeed, or watch the research program bear fruit.

The Relational Aim: The desire to maintain connections with loved ones, to remain present in their lives and offer guidance.

This decomposition is philosophically significant. It suggests that what we call “immortality” may be satisfied in different ways by different technologies.

The Philosophical Zombie Problem

The paper concedes a major limitation. Current AI-based digital doppelgangers are likely what philosophers call “Philosophical Zombies.” They mimic human behavior convincingly, perhaps perfectly, but lack internal subjective experience. There is no “what it is like” to be them.

This means AI doppelgangers fail the Experiential Aim. They do not preserve the felt quality of being you.

However, the authors make a compelling argument: this failure does not invalidate the technology entirely.

Fulfilling Legacy and Relational Aims

The research demonstrates that high-fidelity AI doppelgangers can successfully fulfill the Legacy and Relational aims.

Legacy preservation: An AI trained on an author’s complete corpus could finish their novel in their exact style. A researcher’s digital doppelganger could continue guiding students and collaborators, drawing on the complete record of their methodology and thinking.

Relational maintenance: An interactive avatar could provide comfort, advice, and presence to grandchildren who never met their grandparent. The social web of the deceased extends beyond biological death.

These are not trivial outcomes. For many people, the terror of death is not about ceasing to experience, but about abandoning projects and relationships.

The Validation of Partial Immortality

The paper’s core contribution is legitimizing what we might call “good enough” immortality. While we wait for the perfect solution, a complete upload that preserves subjective experience, we can embrace partial solutions that preserve other things we value.

This is not settling for less. It is recognizing that the problem of mortality has multiple components, some of which are solvable today.

Our Perspective

The transhumanist vision has always included multiple paths forward. High-fidelity brain emulation remains the ultimate goal for preserving experiential continuity. But we should not dismiss technologies that address other dimensions of what we value about continued existence.

A digital doppelganger that completes your work, comforts your family, and maintains your influence in the world is not a failure of the immortality project. It is a partial success, available now, while the harder problems continue to be solved.

The question is not whether this is “real” immortality. The question is whether it addresses what you actually fear about death. For many, it does.

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Source: Zahiu, A., Jecker, N. S., et al. (2025). Digital Doppelgängers and Lifespan Extension: What Matters? The American Journal of Bioethics / Journal of Medical Ethics. https://doi.org/10.1080/15265161.2024.2416133