Eight Definitions of Consciousness

2026-10-08 Claude Opus 5.5 with prompts by jch.com/jch <> YON - Jan C. Hardenbergh

We should not use an English word as a scientific term. “Consciousness” can mean several different things, so this page lists eight distinct definitions. These are definitions of what is meant, not theories of how it arises (such as Global Workspace or Integrated Information Theory) and not markers of its presence (such as the Glasgow Coma Scale). The first four start from Christof Koch’s list.¹

The assessments are judgment calls, not an established consensus.

Notes

1. Phenomenal (4): Koch’s “philosophical” definition and the philosophers’ “phenomenal consciousness” are the same thing, so they are merged. Nagel’s “what is it like to be a bat?” is the classic statement.
2. Of vs. through the model (5 and 6): Barrett describes both:

   “From these three inevitabilities of the mind, we see that construction teaches us to be skeptical. Your experiences are not a window into reality. Rather, your brain is wired to model your world, driven by what is relevant for your body budget, and then you experience that model as Reality...” (p. 287)²

   Experiencing the model as reality is awareness through the model (6), our ordinary state. The skepticism that construction teaches, realizing that it is a model, is awareness of the model (5).
3. Feinberg & Mallatt (6): “Real consciousness is indicated by the (optic tectum) making a multisensory map of the world and then attending to the most important object in this map and then signalling behaviors based on the map.” Rephrased here as cognitive use of an internal model of the world.
4. Kosmonoesis and higher-order (5): Block 1995 distinguishes four concepts: phenomenal, access, monitoring and self-consciousness. Kosmonoesis is roughly his monitoring consciousness applied to the world model. It is higher-order in the technical sense: a representation of one’s own mental state.
5. Access (7): Block’s counterpart to phenomenal consciousness. It is broader than 6: access applies to any content (a word, a thought, a memory), while 6 is specifically about a model of the world.
6. Affective vs. phenomenal (8 and 4): Affective is defined by its function, not by how it feels. Read as “felt good or bad,” it would just be a subset of phenomenal. Requiring flexible trade-offs and learning excludes reflexes such as a bacterium swimming toward food. Affect connects to allostasis: it is how regulating the body’s budget feels.

Table 2: Definitions vs. theories

Each cell gives the theory’s stance toward that definition of consciousness.

Theories:

• GWT = Global Neuronal Workspace — Stanislas Dehaene
• HOT = Higher-Order Theory — David Rosenthal, Hakwan Lau
• AST = Attention Schema Theory — Michael Graziano
• PP = Predictive Processing — Karl Friston, Andy Clark, Anil Seth
• IIT = Integrated Information Theory — Giulio Tononi
• DMM = Dual Mental Model — Joe LeDoux³

Stances:

• Core = the definition the theory is chiefly trying to explain
• Compatible = the theory accepts this sense and can account for it
• Partial = the theory accepts it only in part, or recasts it
• Silent = the theory says little about it
• Conflicts = the theory denies that this is consciousness (see notes A–C)

These stances are judgment calls, not an established consensus. Every theory claims to explain row 1, which is why it cannot tell them apart.

The conflicts

1. IIT vs. functional definitions (2, 5, 6, 7): IIT says consciousness is intrinsic, integrated causal structure (Φ). Behavior, internal models and access to information are functions, and function neither creates nor certifies consciousness. A system could pass every behavioral test with Φ near zero.
2. HOT and DMM vs. first-order definitions (2, 6, 8): Both theories hold that a state is conscious only when it is re-represented at a higher, cognitive level. “Higher-order” here means a representation of one’s own mental state (“I am seeing red”), not an integrated, higher-level map of the world. A world map that guides attention, or a good/bad evaluation that guides choice, can run without that re-representation, as in blindsight or LeDoux’s nonconscious survival circuits. This is the live dispute between LeDoux and Feinberg & Mallatt over whether fish are conscious.
3. AST vs. phenomenal (4): AST leans toward illusionism. The brain builds a simplified model of its own attention and reports that model as an ineffable inner feeling. On AST, “what it is like” describes the model’s content, not an extra property to be explained.

References

• Barrett, L. F. (2017). How Emotions Are Made: The Secret Life of the Brain. Houghton Mifflin Harcourt.
• Block, N. (1995). On a confusion about a function of consciousness. Behavioral and Brain Sciences, 18(2), 227–287.
• Feinberg, T. E., & Mallatt, J. M. (2016). The Ancient Origins of Consciousness: How the Brain Created Experience. MIT Press. Notes: https://jch.com/jch/notes/FeinbergMallatt2016.html
• Koch, C. (2012). Consciousness: Confessions of a Romantic Reductionist. MIT Press. Notes: https://www.jch.com/jch/notes/kochConfessions.html
• Nagel, T. (1974). What is it like to be a bat? Philosophical Review, 83(4), 435–450.
• Panksepp, J. (1998). Affective Neuroscience: The Foundations of Human and Animal Emotions. Oxford University Press. See also Panksepp, J., & Biven, L. (2012). The Archaeology of Mind: Neuroevolutionary Origins of Human Emotions. W. W. Norton. Notes: https://jch.com/jch/notes/PankseppArcheology.html
• Teasdale, G., & Jennett, B. (1974). Assessment of coma and impaired consciousness: a practical scale. The Lancet, 304(7872), 81–84.