Head to head
Emergence vs Higher-Order Thought Theory
Emergence (Principle of Consciousness) and Rosenthal’s Higher-Order Thought, compared field by field from their entries in the Atlas.
At a glance
- Both belong to the Materialism family in Kuhn's Landscape of Consciousness.
- Both treat consciousness as emergent.
- They give the same kind of answer on AI consciousness and mind uploading.
- On life after death, Emergence says “Conditional” and Higher-Order Thought Theory says “No”.
- On meaning and purpose, Emergence says “Uncertain” and Higher-Order Thought Theory says “Humanistic only”.
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The claim
In brief
EmergenceEmergence is the philosophical claim that qualitatively new properties, such as consciousness or psychological states, arise from underlying physical properties governed entirely by physical laws. It is distinguished primarily into weak emergence, which is reducible in principle, and strong emergence, which is fundamentally non-reducible and may necessitate new physical laws.
Higher-Order Thought TheoryDavid Rosenthal holds that a mental state is conscious when its subject has a higher-order thought that he or she is in that state, a thought that need not itself be conscious and does not seem to rest on inference. Mental qualities such as the redness of a sensation exist whether or not they are conscious; Rosenthal explains them separately, by how they map the perceptible properties we can discriminate.
What consciousness is
EmergenceConsciousness is identified as a qualitatively novel property or psychological state arising from physical properties. This concept defines the relationship between mind and matter based on reducibility or non-reducibility to fundamental physics.
Higher-Order Thought TheoryA state’s being conscious consists in the subject being aware of it by way of a suitable higher-order thought that one is in that state.
Big questions
Can AI be conscious?Both agree
EmergenceConditionalIf consciousness is weakly emergent, AI consciousness is certain given sufficient complexity. If strongly emergent, AI consciousness is still possible if non-physical properties emerge from non-biological physical complexity, depending on the meta-psychophysical laws involved.
Higher-Order Thought TheoryPossibleSince consciousness depends on having suitable higher-order thoughts about one’s own states, a system able to form such thoughts would meet the condition in principle.
EmergenceConditionalWeak emergence, being close to Materialism, precludes survival. Strong emergence, particularly in the form of Emergent Dualism, could theoretically generate a nonphysical substance (mind/soul) dependent on, but not strictly identical to, the physical brain, allowing for potential independent existence after death, although this is speculative.
Higher-Order Thought TheoryNoConscious states are natural states of an organism, so nothing remains conscious once those states stop occurring.
Could a mind be uploaded?Both agree
EmergenceConditionalIf consciousness is weakly emergent, duplicating the physical states would duplicate the mental states (likely). If strongly emergent, the non-reducible properties and possible downward causation would need to be perfectly captured and recreated in the new medium, posing significant, perhaps insurmountable, technical and conceptual challenges.
Higher-Order Thought TheoryPossibleIf the relevant first-order states and higher-order thoughts were reproduced, the view gives no principled reason the copy would lack consciousness.
EmergenceUncertainEmergence, especially strong emergence combined with concepts like top-down causation, offers a framework where higher-level properties like consciousness and its associated values could possess genuine causal power, potentially supporting cosmic purpose or meaning, depending on the resulting ontology.
Higher-Order Thought TheoryHumanistic onlyThe theory is a naturalistic account of mental states and carries no cosmic purpose.
Nature of mind
Ontology
EmergenceHighly variable/Contested. Weak Emergence supports reductive Physicalism. Strong Emergence often implies Non-Reductive Physicalism or a need to expand the conception of nature, potentially requiring new fundamental laws (Naturalistic Dualism or Property Dualism).
Higher-Order Thought TheoryPhysicalism (naturalistic functionalism)
Mind and body
EmergenceEmergentist. The mind arises from the body (complex physical systems). The nature of the relationship depends on the type of emergence: Weak suggests reduction in principle; Strong suggests non-reducibility even in principle, often involving downward causation.
Higher-Order Thought TheoryMental states, their qualities, and the higher-order thoughts that make them conscious are all natural states of the organism; Rosenthal expects neural correlates of consciousness to be whatever mechanism produces the higher-order awareness.
Fundamental or emergent
EmergenceEmergent
Higher-Order Thought TheoryEmergent
Qualia
EmergenceQualia are the novel, qualitatively new properties (e.g., sensory qualities) that arise from the physical system. Strong emergence views consciousness (and thus qualia) as the clearest case of a strongly emergent phenomenon, fundamentally irreducible to underlying physical facts.
Higher-Order Thought TheoryMental qualities are fixed by their role in perceptual discrimination and occupy a ‘quality space’ that mirrors the similarities among perceptible properties. Because these qualities do not depend on consciousness, a sensation can have qualitative character without being conscious, as in subliminal perception.
How it works
Mechanism
EmergenceThe principle is the claim that novel, qualitatively distinct properties arise at higher levels of complexity, which is often contrasted with the reductive assumptions of mainstream science.
Higher-Order Thought TheoryA non-inferential higher-order thought that one is in a given state, which makes that first-order state conscious even when the thought itself is unconscious.
Where it is
EmergenceTypically localized in complex biological systems (e.g., brains), although strong emergence proponents may argue that AI consciousness is possible if sufficient physical complexity is achieved, regardless of substrate.
Higher-Order Thought TheoryNot stated
What it does
EmergenceVaries. Weak emergence aligns with standard physical causation. Strong emergence often posits top-down causation, where emergent higher hierarchical levels exert causal force on lower levels, giving the emergent property causal powers.
Higher-Order Thought TheoryNot stated
Evidence and criticism
Testability
EmergenceSpeculative and philosophically contentious. Weak emergence is scientifically aligned in principle. Strong emergence is difficult to test empirically because it posits phenomena are non-deducible from fundamental science.
Higher-Order Thought TheoryConceptually testable
Tests so far
EmergenceNot stated
Higher-Order Thought TheoryNot stated
Criticisms
EmergenceIt is criticized by reductive physicalists (like Eliminative Materialists) as having little explanatory value, being superfluous, or acting as a 'restatement of a miracle' that fails to explain *how* unconscious complexity yields consciousness. Strong emergence specifically challenges the causal closure of the physical world.
Higher-Order Thought TheoryFirst-order theorists argue that higher-order awareness is an unneeded extra ingredient, and deflationists say being aware of a conscious state is like ‘smiling a smile’. Rosenthal replies that a deflated awareness cannot explain the contrast between conscious and unconscious states.
Sources
Key sources
Emergence
- The Re-emergence of Emergence: the Emergentist Hypothesis from Science to Religion, P. Clayton and P. Davies (2008)
- Strong and weak emergence, D. Chalmers (2008)
- Why reductionism does not work, G.F.R. Ellis (2019)
Higher-Order Thought Theory
- Rosenthal’s Higher-Order Thought, Landscape of Consciousness, David Rosenthal (2005)