Published on January 22, 2025 11:48 AM GMT
tl;dr: If a copy is not identical to the original, MWI predicts that I will always observe myself surviving failed Mars teleportations rather than becoming the copy on Mars.
Background
The classic teleportation thought-experiment asks whether a perfect copy is "you". This normally presents as a pure decision problem – do you step into the teleporter? But I suggest we can construct real experiments yielding observational evidence about personal identity.
The Quantum Mars Teleporter Protocol
Consider a "teleporter" connecting Earth & Mars with two key properties:
1. It creates a perfect copy on Mars using scanning
2. The original is destroyed with probability p = 0.999 (controlled by quantum randomness)
Under different identity theories, this yields divergent predictions:
- If copy ≠ original: Due to quantum immortality, the observer should always find themselves as the surviving original (in branches where the original is not destroyed)
- If copy = original: The observer should usually (~99.9%) find themselves on Mars.
By repeating this experiment n times, we could achieve arbitrary statistical confidence. An observer consistently finding themselves as the surviving original would constitute strong evidence against copy = original.
Objections & Responses
1. The Presumptuous Philosopher Problem
One might object this merely recapitulates the Presumptuous Philosopher – resolving metaphysical questions through observer-counting. However, unlike PP, this generates falsifiable predictions about specific observations.
2. Reference Class & Observation Selection
The "someone would see this somewhere" objection fails because:
1. We can make p arbitrarily small
2. The evidence is the personal observation stream
3. Results are demonstrable to third parties in each branch
3. Quantum Foundations Dependency
The proposal does rely on:
1. Many-Worlds Interpretation
2. Quantum Immortality
3. Particular theories of consciousness/identity
This is a limitation but not fatal – we could construct classical variants (see below).
Also, the experiment itself can prove quantum immortality. If the cumulative probability of a Failed Teleporter were less than 1 in a trillion (with Earth's population at 10 billion), it would strongly suggest MWI plays a role and the death-risk event actually occurs.
4. Conversation of evidence violated
Finding myself on Mars after QMT proves nothing: a copy gains no new information. This appears to violate evidence symmetry: if something strongly evidences X, its absence should strongly evidence not-X. However, this isn't always true: if someone steals a $100 bill from a table, it strongly suggests they're a thief. If they don't steal it, this isn't evidence they're not a thief.
Classical Variant: The Million Copies Test
Create 10^6 exact copies. Under copy = original, P(being original) = 10^-6. Under copy ≠ original, P(being original) = 1. Observing oneself as original would constitute strong Bayesian evidence.
Advantages vs QMT:
- No quantum metaphysics required
- Cheaper per-trial cost
Disadvantages:
- More vulnerable to anthropic/PP objections
- Requires massive computational resources
- Ethical concerns about copy welfare
Natural Experiments
We may already have relevant data:
1. Digital Consciousness test: Those expecting future digital copies should find themselves as copies more often than not (under copy = original). I have a large digital footprint and interest in being copied and recreated. Future emulations (not simulations) of me are plausible – they'll know they're digital models. However, finding myself still here in 2025, not as a future digital mind, suggests either my digital copies won't be me or such copies won't exist.
2. *Continuity of consciousness content test: If consciousness breaks during sleep, quantum immortality predicts insomnia. If night dreaming breaks continuity, each day can be viewed as an independent person dying at day's end. Sleep impossibility would manifest nightly: due to MWI, timelines would always exist where I can't achieve deep sleep. I'll know tomorrow if severe insomnia occurs.
Conclusion
While ambitious, this proposal offers a path to empirically testing theories of personal identity that were previously considered purely philosophical. The key insight is leveraging quantum mechanics to create situations where different identity theories make contradictory experimental predictions.
Discuss
