Study notes: Can Two Minds Share One Experience

One concrete experiential occurrence would participate in two distinct subjects at once. That is stronger than seeing the same object, receiving the same information, or having experiences that feel exactly alike. It is different from merging the two people into one subject. The proposal is that occurrences and subjects need not have matching boundaries. Distinct subjects might overlap in an occurrence. An encompassing subject might coexist with smaller ones. Or coupling might transform or extinguish the smaller unities. Each requires a different causal arrangement, and a graph on paper establishes none of them.

Digital computation is legible to nature when its content is in the causal nexus: the content-bearing distinctions participate in how the system proceeds, and the interpretation is constrained by what would happen under relevant changes. That secures actual computation and no more. A logic engine can be effective without literally understanding anything. A minded system can literally understand without undergoing phenomenal experience, which is the authors’ tentative position on current AI. The three demands are actual computation, minded understanding and phenomenal occurrence. The essay agrees that the first does not establish the third, and denies that a computational account claimed it did.

Earlier, an experience was an abstract structure grounded in a concrete process, and a subject was an inhabitant of the multiverse, individuated by its constitutive abstractions. Further realizations added to its reality weight. Now the experience is the concrete occurrence itself. Worldliness means that a subject and its experiences are constituted by the actual processes that sustain them. On the former account an experience was individuated by its relation to one subject’s phenomenal field, so it could not belong to two, while the subject could be realized across worlds. The reversal runs from subjects shared across worlds with experiences exclusive to subjects, toward worldly subjects that might share an experience.

He asks which physics, and in virtue of what. On Wolfram’s account, gravity and quantum mechanics can themselves describe emergent regularities, so their status as physics does not make them a science of grounding. Calling a more fundamental description physical does not establish its priority over every organizational description. The term “psychophysical laws” already suggests the form of the explanation and the vocabulary on one side of it. An identity or an account of constitutive organization might revise that division. The essay objects to treating the framing as compulsory, and does not claim that a law could never express a constitutive relation.

• Level. The identity is with a concrete dynamical organization: certain representational vehicles, sustained in a particular mode of content-sensitive regulation, are experiential occurrences. The material may vary. A description or an input-output imitation of the dynamics does not establish them.
• Acquaintance names the actual regulatory involvement with vehicles, which requires that the vehicle exist. The regulation is epistemic because it addresses content through its vehicles. Supplying blood or cooling a processor does not qualify.
• Dreams. The vehicle and its regulation can be actual while the represented object is absent or the content false.
• Not panpsychism. Experience is identified with particular organizations of activity. Their constituents need not be experiential, and mere causal efficacy, as in a thermostat, does not qualify. Feigl drew the same line.
• Sharing. Identity theory does not say that experiences can be shared. The answer must respect the identity conditions of the occurrence. We may not individuate each experience by a unique owner and then present the impossibility of sharing as a discovery.

Three relations are run together: the represented relation (the cup is beside the plate), their being experienced together, and the causal coordination that sustains the experiences. A graph of the field is useful once its edges are specified. “Experienced beside” is not transitive, and a transitive closure gives reachability, not joint experience. Suppose A and B share one occurrence, B and C another, C and A a third. The diagram is connected, yet each link might be maintained within the three distinct regulatory organizations, with none sustaining the whole as one perspective. A connected component then overcounts unity, and a maximal-clique rule would need its own argument. The objection is to the wrong choice of edges, not to graphs.

A and B each sustain a minded perspective and some phenomenal activity, and their cognitive economies partly overlap. Within the overlap is a representational process that both regulate in compatible ways, and their contributions jointly sustain one experiential occurrence. Agreement that an object is red is not enough. The demands must be compatible at the level of the ongoing vehicle: its state, timing, maintenance and relations to other processing. A and B can surround the occurrence with different associations and uses, so their total experiences differ. The proposal is partial overlap, not identity of two phenomenal lives.

Constitutive dependence is not necessarily exclusive dependence. A single concrete process can include compatible contributions from both organizations while participating in two larger economies. Not every feature of either surrounding subject becomes a constituent of the occurrence’s local qualitative character. The proposal fails if all of A’s organization enters indivisibly into the identity of every experience A has. It also fails if participation in two organizations necessarily individuates two occurrences even when the contributions are compatible. What is needed is a principled account of which dependencies constitute the occurrence and which connect it to a larger perspective. The essay cites Goff and Roelofs as defending phenomenal sharing between overlapping subjects.

Regulation is temporally thick, and on the account this explains the thickness of the phenomenal now. Sharing therefore requires compatible involvement sustained over the interval, and a passing coincidence would not establish a shared now. The centers also retain dynamics that can pull them apart, since each has different ongoing work. That overlap often ends in divergence is a further expectation, and joint regulation might instead stabilize it. At divergence the author favors experiential continuity with qualitative change: the redness might become more imagery-like for A while staying perceptual for B. He does not favor a piece of experience vanishing while a nonphenomenal representation remains. Other outcomes are left open.

Two systems sharing an occurrence need not sustain a larger subject. A larger subject need not extinguish the smaller ones. And parts of a subject need not be subjects. IIT’s exclusion postulate selects one maximal complex among overlapping candidates. The essay imposes no exclusion in advance and lets the causal account decide whether smaller unities survive. The author’s former Platonic account and IIT both owe an account of experiential continuity when subject demarcation changes. Here an occurrence can continue while the organizations participating in it regroup, so no discontinuity follows from a rule of exclusive ownership. Nesting must still be earned at each scale: a subject is not any region with a boundary drawn around it.

Cochrane argues that some of the twins’ experiences are most likely shared tokens while they remain distinct subjects. He appeals to where the content is processed, and acknowledges that practical methods cannot directly establish numerical identity. The alternatives: one brain constructs an experience from information originating in the other, or the experiential process itself participates in both economies. The two could yield similar reports. The case motivates the distinction without settling the mechanism. Pinto and colleagues read their split-brain findings as divided perception without two independent perceivers, and critics disputed the inference from unified response control. The essay’s lesson is that shared control of a response is evidence about organization and not a count of subjects.

• Messages. A report, however accurate, does not make the reported occurrence a constituent of the recipient’s experience.
• Synchronized copies. Exact agreement in values leaves two concrete occurrences. Copying a vehicle is not sharing its numerical identity.
• One memory location or the same hardware. A jointly readable buffer need not be an experiential vehicle.
• Joint regulation of one process, with both contributions constitutive of its experiential mode. This is the candidate. The dependence runs through the maintenance of the occurrence.

The subject count stays open: two economies with a shared part, a third encompassing economy, or systems so transformed that their former subjecthood does not persist.

The strongest vulnerability is individuating a local occurrence within a relationally constituted whole. If a shared process cannot be identified without arbitrarily subtracting essential aspects of A or B, the essay has described overlapping physical support for two experiences. The expectation of divergence would be wrong if joint contributions stabilize a common process indefinitely. Partial sharing may be impossible if every arrangement that sustains the process forms one exclusive subject. Conceivability cannot decide because a vehicle has one concrete history. A diagram can assign it one content in A and another in B while the assignments make incompatible demands on its transitions. On the hard problem: identifying experience with a mode of regulation is a hypothesis about what experience is, and does not derive feeling from regulation.

Establish that there is one occurrence. Establish that two perspectives remain. Then show how their regulatory involvement can constitute the first without abolishing the second. A subject can be the organized process through which experiences participate in a perspective. Its unity is real if its constitutive dependencies are real, and need not be visible as another item in the experienced scene.