Essay · Philosophy of mind
The TimeSlice Argument
When Does an Experience Happen?
If a conscious experience takes time, then no single moment of the process is the moment it occurs. That turns out to be harder to live with than it sounds.
You hear three notes and you hear them as a phrase. Not three separate hearings in a row, and not a hearing of the third note with the first two attached as memory. One experience, of a sequence.
Now suppose that experience has a physical basis in your brain, and suppose that basis takes time. Almost everyone thinks it does — a single instant of brain activity is too thin to carry a phrase. You need a process, running over some interval.
So: the experience is one thing, and its physical basis is spread out. Divide the interval into a beginning, a middle and an end. When does the experience happen?
It sounds like a technicality. Every answer costs something.
The three answers
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It happens at the end, once the process is complete
Then the earlier stages are over. The experience depends on physical events that no longer exist, and it cannot have caused anything attributed to it during those stages, because that work was already done without it. It becomes the smoke, not the fire.
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It happens at the beginning
Then the rest hasn't occurred. Either the later stages make no difference to it — in which case they weren't part of its basis — or they do, and the experience is already shaped by something contingent. What happens after is a result of circumstance, not just physical law. A meteor could hit you a millisecond later.
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It happens in the middle
Both problems at once. The present stage is asked to hold what is no longer there and what is not yet there. We can call it memory for the past and anticipation for the future, but there is no classical physical process that can be without the possibility of error. A trace that might have been wrong is not the thing it records.
You can say the experience is present at every stage. But then either there are three experiences rather than one, or there is a single one persisting across them — and what makes it single is the question we started with.
Or you can say the experience simply is the whole process, and asking when it occurs is a badly formed question. That is the best answer available. But it requires the stages to be genuinely bound into one thing rather than merely lined up, and that binding is what needed explaining.
Early work on this argument
I wrote this as the "TimeSlice Argument" in 2012 and shared it with a few of my fellow colleagues and my supervisor as a proposed appendix to my thesis. It sets the argument out more carefully than I have, in terms of a minimal phenomenal state Pm jointly realised by brainstates M1, M2 and M3, and then turns on a single question:
Now the question is, when does Pm occur?
— "The Source of Externalism about Phenomenal States," the cut appendix, 2012
It works through the three placements in turn and ends by concluding that we are surrounded by absurdities on all sides. The exits were available at the time. Justin Fisher had argued in 2007 that nothing mental is fixed by what is in the head at a time, and preferred a history-oriented teleo-functionalism; Dennett had run similar cases to absurd consequences and ended in eliminativism. The symmetry between those exits is what made me accept this was a deep problem rather than take one.
Where the argument leads now
The original argument assumes that the experience must occur somewhere in the interval occupied by its physical basis. That can be denied: the experience may simply be the temporally extended process. But this moves the problem from location to unity. What makes the stages one experience rather than a sequence of related states?
Builes and Impagnatiello's Time-Slice Internalism presses on the same point. Their view allows physically identical states to differ in experience because of what they would do under other conditions. The meteor case tests the reach of those dispositional powers. If they guarantee the later course, the meteor cannot interrupt it. If they describe only what would happen without interruption, the frozen duplicate returns. In either case, the actual state alone does not settle the experience. The account is paying in unactualised coin.
This is where the argument now seems to lead. The experience is not located at one stage because it is one across the interval. But saying "the whole process" is not yet an explanation. The stages must be genuinely fused, and their identity may depend partly on the possibilities still open to them.
My own approach is Hypermodal Realism: the actual state at an instant does not exhaust what an experience is, because its unrealised possibilities help individuate it. I develop that view on QualiaSpace, where you can also find my wife Camilla Karlsen's work on Qualia Fusion Emergence.
Sources
- Justin C. Fisher, "Why Nothing Mental is Just in the Head," Noûs 41(2), 2007. Cited in my 2012 draft as the strongest case against locating experience in an instant. Open offprint
- David Builes and Michele Odisseas Impagnatiello, "Experience and Time: A Metaphysical Approach," Analytic Philosophy. PhilArchive
- Daniel Dennett and Marcel Kinsbourne, "Time and the Observer: The Where and When of Consciousness in the Brain," Behavioral and Brain Sciences 15(2), 1992 — the timing cases, and the deflationary road out of them. DOI
- Yakir Aharonov and Lev Vaidman, "The Two-State Vector Formalism: An Updated Review" — forward and backward evolving states, and weak values. PDF
- "Retrocausality in Quantum Mechanics," Stanford Encyclopedia of Philosophy — Cramer, Kastner, Price, Wharton, Sutherland, Adlam, and the standard objections. SEP
- Michael H. Herzog, Thomas Kammer and Frank Scharnowski, "Time Slices: What Is the Duration of a Percept?", PLOS Biology 14(4), 2016 — the two-stage model: continuous unconscious processing, discrete conscious percepts, arriving late. DOI
- Izchak Miller, Husserl, Perception and Temporal Awareness, MIT Press, 1984 — the Principle of Simultaneous Awareness, and the premise this argument rests on.
- Barry Dainton, "Temporal Consciousness," Stanford Encyclopedia of Philosophy — the map of the field, and where to start. SEP
- Camilla Karlsen, Does Free Will Matter? Agent Causation and Qualia Fusion Emergence, Master of Philosophy thesis, University of Oslo, 2020 — an account of conscious unity as fusion emergence.
- Christian Lains, "The Source of Externalism about Phenomenal States," 2012 — the cut appendix in full, with its dated carriers. Read
- Andrés Gómez Emilsson, "A (Very) Unexpected Argument Against General Relativity As A Complete Account Of The Cosmos," Qualia Computing, March 2016 — the mereological version. Read