Part II: Identity Thesis

The Structure of Experience

Introduction

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The Structure of Experience

If experience is cause-effect structure, then the kind of experience is determined by the shape of that structure. Different phenomenal properties correspond to different structural features.

Two levels of structural claim are at work here, and they should be distinguished. The first: different experiences have different structures. Specific phenomenal features—the redness of red, the sharpness of fear—correspond to specific structural motifs in cause-effect space. These extractable aspects of experience (the narrow qualia introduced in Part I's gradient of distinction) can be compared across moments and across systems by measuring structural similarity. This claim is relatively modest and empirically tractable. The second is stronger: the unified moment of experience IS the full cause-effect structure. Not just that the parts have geometry, but that the whole IS geometry—the broad qualia, everything-present-at-once, is identical to the intrinsic cause-effect structure in its entirety. The geometric affect framework (next section) addresses the first claim: it characterizes narrow qualia as structural motifs. The identity thesis above makes the second: broad qualia is cause-effect structure. They are logically independent—you can accept that affects have geometric signatures without accepting that experience is nothing over and above structure. But if the identity thesis holds, then integration ( $\intinfo$ ) becomes the bridge: it measures how much the broad qualia exceeds the sum of narrow qualia, the quantity of unified experience that survives any attempt to decompose it into characterizable parts.

IIT proposes that the essential properties of any experience are:

Intrinsicality: The experience exists for the system itself, not relative to an external observer.
Information: The experience is specific—this experience, not any other possible one.
Integration: The experience is unified—it cannot be decomposed into independent sub-experiences.
Exclusion: The experience has definite boundaries—there is a fact about what is and isn’t part of it.
Composition: The experience is structured—composed of distinctions and relations among them.

These are translated into physical/structural postulates:

Intrinsicality $\to$ Cause-effect power within the system
Information $\to$ Specific cause-effect repertoires
Integration $\to$ Irreducibility to partitioned components
Exclusion $\to$ Maximality of the integrated complex
Composition $\to$ The full structure of distinctions and relations

Engaging with IIT Criticisms

The identity thesis inherits IIT’s strengths and its controversies. Intellectual honesty requires engaging with the most serious objections.

The expander graph problem (Aaronson, 2014): Simple systems like grid networks may have very high $\intinfo$ under IIT’s formalism despite seeming clearly non-conscious. If $\intinfo$ tracks consciousness, even grid wiring diagrams are richly experiential. Response: This objection targets exact $\intinfo$ as defined by IIT 3.0’s formalism. The framework here works with proxies—partition prediction loss, spectral effective rank, coupling-weighted covariance—that are calibrated against systems with known behavioral and structural properties (biological organisms, trained agents, evolved CA patterns). Whether exact $\intinfo$ maps onto consciousness for arbitrary mathematical structures is a question about the formalism, not about the structural principle. The claim is not “any system with high $\intinfo$ is conscious” but “experience is integrated cause-effect structure at the appropriate scale,” where “appropriate” is constrained by the full structural profile, not a single number.

Computational intractability: Exact $\intinfo$ is NP-hard to compute for systems beyond trivial size. Response: Acknowledged. The V11 experiments (Part I) use spectral proxies validated by convergence with exact measures on small systems. All empirical claims rest on proxies, not exact $\intinfo$ . This is analogous to using Boltzmann entropy rather than Gibbs entropy for practical calculations—the conceptual definition and the computational tool can diverge without invalidating either.

Over-attribution: If any system with $\intinfo > 0$ is conscious, thermostats are conscious. Response: The gradient of distinction (Part I, Section 1) makes this explicit. Yes, a thermostat has minimal cause-effect structure. Whether that constitutes minimal experience or no experience is an empirical question the framework does not prematurely answer. There is a continuum, not a binary threshold. The structural affect dimensions are measurably present only in systems with substantial integration, self-modeling, and viability maintenance—not in thermostats.

The real vulnerability: The identity thesis, like any metaphysical identity claim, cannot be empirically verified in the standard sense. You cannot compare experience “from the outside” with cause-effect structure “from the inside” because there is no vantage point from which both are simultaneously accessible. What can be tested: whether the structural predictions (affect motifs, dimensional clustering, ι dynamics) track human phenomenal reports and behavioral measures. If they do, the identity thesis gains inductive support. If they do not, the structural framework fails regardless of the metaphysics.