Contribution
A compact statement of the Damasios’ “new theory” of consciousness, the same thesis as their book Feeling and Knowing (2021, cited as ref. 7) and as the Neural Computation paper LIT-387. What it adds to Damasio and Carvalho (2013, LIT-388) is the step from feeling to consciousness, feelings as what make every content conscious, and a physiological reason why feelings differ in kind from exteroceptive images: in interoception the mapped object can act on the map.
Key insight
Ordinary images of the world tell you what is out there but not whose image it is. Homeostatic feelings do both at once, because they are about the body and are partly made of it: the gut that the brain maps can also reach the mapping neurons directly, chemically and electrically. A continuous stream of such feelings, even the faint feeling of simply existing, tags every other content as belonging to this organism, and that tagging is what consciousness is.
Assumptions
- A definition of consciousness. Consciousness is the spontaneous identification of mind contents with an owner (“Consciousness”), not integration, scale of integration or attention. Everything else follows from this choice, and the essay does not argue for it beyond setting it against the alternatives it names.
- Sensing versus minding. Sensing needs no nervous system and “dispenses with representations”; minds are streams of mapped images and need nervous systems (“Sensing and minding”).
- Homeostatic feelings are conscious in themselves (“How is consciousness made”, paragraph 2): “Homeostatic feelings are not conscious because they borrow consciousness from some other process.”
- A threshold. Feelings support continuous consciousness when above a threshold, and are generated continuously in the awake state.
Key results
There are no results in the experimental sense. The claims and their offered support:
- The identification claim (“How is consciousness made”, paragraphs 1–5). Feelings provide “the identification of a particular mind with a particular organism”; self-consciousness builds on this when perceptions, memories and reasoning are connected to the organism and to its history. Support: argument from the definition.
- The evolutionary claim (paragraph 3). Homeostatic feelings were “the inaugural phenomena of consciousness”, selected because their knowledge allowed life regulation to be guided “in an overt manner”. Support: none given beyond the advantage stated.
- The hybrid mechanism (“How do living organisms generate homeostatic feelings?”, Table 1). Interoceptive pathways: poorly myelinated or unmyelinated (Aδ/C) axons; non-synaptic as well as synaptic transmission; slow (seconds to hours) as well as fast time scales; blood–brain barrier absent or with gaps; monoamines, acetylcholine and neuropeptides. Exteroception, movement and cognition: well myelinated (Aα/Aβ), predominantly synaptic, very fast (μs–ms), a continuous barrier, glutamate and GABA. Support: the anatomical contrast, cited to Carvalho and Damasio (2021).
- Coma (“Impaired consciousness”, paragraph 1). Focal damage to the posterior brainstem (nucleus tractus solitarius, parabrachial nucleus, periaqueductal grey) causes coma by compromising integrated body representations and “severing … their links to the exteroceptive mental contents”; “small brainstem lesions can have a devastating effect on consciousness, whereas even extensive lesions of the cerebral cortex may not”. Support: Parvizi and Damasio (2001, 2003).
- Anaesthesia (paragraph 2). General anaesthetics act on “the plain ‘sensing and detecting’ process”, the membrane level that is the first link of the chain to feeling, and so suspend interoception and exteroception together; they halt plant activity too. Support: Baluška et al. (2016).
Claims
| id | claim | strength | support |
|---|---|---|---|
| C1 | Consciousness is the spontaneous identification of mind contents as belonging to one’s organism | a definition, not a finding | stated (“Consciousness”) |
| C2 | A continuous flow of homeostatic feelings provides that identification, and lends consciousness to exteroceptive images | weak: argued from the definition; no test proposed | ”How is consciousness made” |
| C3 | Homeostatic feelings were the first conscious phenomena in evolution | weak: an adaptive story, no comparative evidence | paragraph 3 of the same section |
| C4 | Interoceptive pathways differ from exteroceptive ones in myelination, synaptic mode, time scale, barrier and transmitters | moderate as anatomy, as cited; the essay gives no numbers | Table 1, ref. 8 |
| C5 | Because of C4, feelings are hybrid: map and body interact and commingle | weak: an interpretation of C4 | ”How do living organisms generate homeostatic feelings?” |
| C6 | Small posterior brainstem lesions abolish consciousness, extensive cortical lesions may not | moderate as clinical observation, as cited | refs 9–10 |
| C7 | General anaesthetics act below feeling, at membrane-level sensing | weak: inferred partly from their effect on plants | ref. 11 |
| C8 | Consciousness needs nervous systems but is not produced by them alone; it requires their partnership with the body | weak: the essay’s conclusion from C2–C5 | ”Conclusion” |
Concepts
- homeostatic feelings: feelings generated by life regulation, from interoception, distinguished from emotional feelings. Salient ones (hunger, thirst, pain, well-being, malaise, desire) and those near equilibrium (“feelings of life/existence”).
- sensing/detecting: response to conditions, possible without a nervous system or representations; shared by bacteria and plants.
- minding: having representations (“mapped patterns” or “images”) built with a nervous system.
- hybrid: of a feeling, being at once neural/representational and non-neural/bodily, because the mapped object and the map “commingle”.
Connections
- Damasio and Carvalho (2013), LIT-388. The same brainstem nuclei and the same unmyelinated-fibre proposal, carried from feeling to consciousness. The 2013 paper offered unmyelinated fibres as a hypothesis about the root of sentience; this essay treats the contrast in Table 1 as the mechanism.
- LIT-387. The parallel Neural Computation statement, unread; its abstract and this essay’s opening summary agree almost verbatim.
- Integrated information and attention. The essay cites Tononi et al. (2016), Dehaene (2014) and Graziano (2021) as solutions that study integration or attention instead of subjectivity. The record holds IIT 3.0 (LIT-445) and the global workspace (LIT-631); the rivalries are declared on the LIT.
- Chalmers (LIT-406) is cited as the source of the notion that the problem cannot be solved within biology; Goff (2019) for physics.
Bearing on the record
- THEORY-045. Supports the “present throughout waking experience” clause with the essay’s feelings of existence, generated continuously while awake. On map versus prediction, it offers a third reading, which the theory does not list: the feeling is partly constituted by the body state, not only a map or a prediction of it. Its evidence for that is anatomical (C4), and it does not address prediction.
- THEORY-090. Supports the subcortical clause with clinical evidence (C6), which goes further than LIT-388: it is about consciousness, not only feeling. On the function clause, it describes feelings as knowledge for overt regulation and does not say whether the earliest feelings override behaviour or weigh options, so it does not settle the rivalry with THEORY-101.
- Filed as THEORY-093. Consciousness is supplied by homeostatic feeling: contents are conscious when tagged as one’s own by a continuous interoceptive feeling, and its loss follows the loss of brainstem integration of body signals. It would extend THEORY-045 from affect to consciousness.
- No ML instruction. Nothing here belongs in the anthology.
Limitations
- No data and no test. The essay does not say what result would refute the identification claim.
- The definition carries the argument. A theory of access or of integration is not refuted by being told consciousness is something else.
- Coma and anaesthesia do not separate the accounts. Brainstem lesions and anaesthetics abolish arousal and every cortical process downstream as well, so their effects are what every theory predicts.
- Plant evidence. That anaesthetics halt plant activity shows they act on membranes; it does not show where in an animal their effect on consciousness lies.
Open questions
- Can feelings of existence be shown to be present when exteroceptive contents are conscious, and absent when the same contents are processed without awareness? That is the test the “lending” claim invites.
- Would blocking interoceptive signalling while sparing arousal abolish consciousness of exteroceptive images, as C2 requires? Spinal or vagal deafferentation cases bear on this, and the essay does not discuss them.