Higher-order theory (HOT)
Explanation
David Rosenthal and other philosophers have defended since the 1980s the Higher-Order Theory (HOT): a mental state is conscious when accompanied by another mental state, of higher order, that represents it. That is, I feel pain consciously not by having a pain state, but by also having a thought about that state: I am feeling pain.
The underlying intuition: conscious states are those the subject is aware of. Being aware requires a second-order representation that monitors the first-order one. Without that meta-representation, there would be mental processes occurring but the subject would not know about them, they would not be conscious in the full sense.
There are variants. Rosenthal's Higher-Order Thought (HOT) proposes that the meta-representation is a thought. Lycan's Higher-Order Perception (HOP) proposes that it is an inner perception. Kriegel's Self-Representational Theory proposes that it is an intrinsic self-reference of the state itself, without requiring a separate state.
This family of theories explains certain phenomena well: why automatic processes (such as driving a familiar route without remembering it) can occur without consciousness; why pathologies of metacognition (such as blindsight, where patients detect stimuli without being aware of them) involve perception but not meta-representation; why conscious reports correlate with prefrontal activation (associated with metacognition).
The criticisms are sharp. First: doesn't this generate an infinite regress? If I need a second-order state for the first-order one to be conscious, won't I need a third-order one for the second-order, and so on? Second: would animals without complex metacognition (insects, fish) not be conscious at all? Third: erroneous meta-representations can produce apparent phenomenal experiences without a corresponding first-order state (confabulation), complicating the theory.
HOT remains one of the main families of theories of consciousness discussed in analytic philosophy, and has supporters in neuroscience (such as Hakwan Lau's higher-order perceptual theory). It competes with theories such as GNW (Global Neuronal Workspace), IIT (Integrated Information), and various first-order forms. None has managed to dominate the field, reflecting the intrinsic difficulty of the problem.
Strengths
- Articulates the reflexive dimension of human consciousness.
- Compatible with the neuroscience of meta-cognition.
- A theoretical family with multiple refinable variants.
- Naturally articulable computationally.
Main critiques
- Non-human animals seem to have consciousness without complex meta-representations.
- Risk of regress: does the meta-state need a meta-meta-state?
- Does not explain qualia.
- Empirical critique: prefrontal activation does not seem necessary for basic experience.