Key Takeaways
1. The Cortical Fallacy: Consciousness is Not Born in the Cortex
If we are going to uphold the hypothesis that the cortex is the seat of consciousness, then these lively animals – and the expressive, emotionally responsive children that Merker observed at DisneyWorld – must in some sense be unconscious.
Challenging dogma. For 150 years, neuroscience has largely assumed that consciousness resides in the cerebral cortex, the brain's impressive outer layer. This "cortical fallacy" is deeply ingrained, leading to the belief that complex thought and subjective experience are exclusively cortical functions. However, compelling evidence from patients and animal studies directly contradicts this long-held assumption.
Evidence against. Patients born without a cortex (hydranencephaly) or animals with surgically removed cortices (decortication) exhibit behaviors inconsistent with a "vegetative state." They display wakefulness, emotional responses like pleasure and aversion, and goal-directed actions. This suggests that a fundamental form of consciousness persists even in the absence of the cortex, challenging the notion that it is the sole seat of subjective experience.
Ethical implications. The cortical fallacy has profound ethical consequences, as seen in the debate over treating hydranencephalic children as insensate. If these individuals are indeed conscious, denying them pain relief or emotional care based on a flawed theory is a grave error. The evidence demands a re-evaluation of where consciousness truly originates, moving beyond mere anatomical size to functional necessity.
2. Consciousness is Fundamentally Feeling (Affect)
Apparently alone among mental functions, feeling is necessarily conscious.
Beyond cognition. While perception, memory, and language are often considered the hallmarks of consciousness, scientific evidence overwhelmingly shows that most cognitive processes occur unconsciously. We can perceive, learn, and even make complex decisions without explicit awareness. This raises a critical question: if so much mental life happens "in the dark," what is the unique function of consciousness?
The essence of feeling. The answer lies in feeling, or affect. Unlike cognitive functions, a feeling, by its very definition, must be felt. An "unconscious feeling" is an oxymoron. Whether it's hunger, fear, joy, or sadness, the subjective quality of these states is inseparable from their existence. This makes feeling the foundational form of consciousness, the irreducible core of subjective experience.
Causal power. Feelings are not mere byproducts; they are intrinsically linked to our biological needs and drive our voluntary behavior. They provide an internal compass, signaling what is "good" or "bad" for our survival and reproduction. This inherent value-laden quality of feelings gives them causal power, guiding our choices and actions in ways that purely unconscious information processing cannot.
3. Feelings are Biological Demands for Work
Freud, you will recall, defined ‘drive’ as ‘a measure of the demand made upon the mind for work in consequence of its connection with the body’.
Homeostatic imperative. Feelings are the subjective manifestation of our biological drives, which are fundamentally homeostatic. Our bodies must maintain a narrow range of viable states—temperature, hydration, energy levels—to survive. Deviations from these "expected" states generate "error signals" that demand corrective action.
Valence as value. These error signals are experienced as feelings, which are hedonically valenced: they feel "good" (pleasure) or "bad" (unpleasure). This valence is not arbitrary; it directly reflects the biological significance of the need.
- Thirst feels bad, quenching it feels good, because hydration is vital.
- Hunger feels bad, eating feels good, because energy is essential.
- Fear feels bad, escaping danger feels good, because safety is paramount.
Guiding action. The conscious experience of these feelings compels us to act. Unlike automatic reflexes, feelings guide voluntary behavior, allowing us to make choices in uncertain situations. This adaptive advantage enables us to navigate complex environments and find novel solutions when innate responses are insufficient.
4. The Brainstem is the Hidden Spring of Consciousness
Apparently, therefore, the only part of the brain that we know to be necessary for arousing consciousness as a whole has an equally powerful influence over another mental function, namely feeling.
Beyond the cortex. If the cortex is not the source of consciousness, where is it? Research points to the brainstem, an ancient, evolutionarily conserved structure. Tiny lesions in the upper brainstem can obliterate consciousness entirely, leading to coma or a vegetative state. This suggests the brainstem is not just a "power cable" but the very wellspring of subjective experience.
Affective core. The brainstem's reticular activating system is crucial for arousal, but this arousal is not merely a quantitative "level" of wakefulness; it has qualitative content: affect. Deep brain stimulation in this region can evoke profound emotional states like sadness or joy, even in individuals with no prior psychiatric history. Functional neuroimaging also shows peak activity in the brainstem during intense emotional experiences like grief or orgasm.
The PAG's pivotal role. All affective circuits converge on the periaqueductal grey (PAG) in the midbrain. The PAG acts as a central hub, integrating internal needs with external opportunities to prioritize which affect will govern the next action. This "decision triangle" orchestrates emotional behaviors and is the main output center for feelings, making it the primal self and the source of our sentient being.
5. Life Itself Minimizes Free Energy (Uncertainty)
All self-organizing systems, including you and me, have one fundamental task in common: to keep existing.
Resisting entropy. Living organisms are "self-organizing systems" that must actively resist the universal tendency towards disorder and dissipation (entropy). This fundamental imperative to "keep existing" is achieved by minimizing "free energy," a concept from physics that, in biological terms, equates to minimizing unexpected events or "surprisal."
The Markov blanket. Self-organizing systems achieve this by forming a "Markov blanket," a statistical boundary that separates their internal states from the external world. This blanket allows the system to infer the hidden causes of its sensory states and act purposefully to maintain its integrity. This process of active inference is akin to a primitive form of perception and agency.
Bayesian inference. The brain, as a self-organizing system, operates like a "Bayesian brain." It constantly makes and revises "best guesses" about the world by comparing sensory evidence with its internal "generative model" (prior knowledge). This continuous process of updating predictions to minimize prediction error is the core mechanism by which living things reduce uncertainty and ensure their survival.
6. The Brain is a Predictive Hierarchy
The brain is somewhat desperately, but expertly, trying to contain the long and short-term effects of environmental causes on the organism in order to preserve its integrity.
Layered predictions. The brain implements a complex "predictive hierarchy" to minimize free energy. This hierarchy extends from the ancient, core brainstem (generating species-specific, innate predictions) to the more recently evolved cortex (generating flexible, context-dependent predictions). Each level predicts the sensory input it expects from the level below, and only "newsworthy" (unexpected) information, or prediction errors, are propagated upwards.
Temporal and spatial scales. This hierarchy unfolds over progressively smaller temporal and spatial scales. Core predictions are broad and apply universally, while peripheral predictions are fleeting and highly specific. This allows the brain to efficiently manage uncertainty, focusing resources where they are most needed.
Action and perception. The brain's generative model not only predicts sensory input (perception) but also guides action. Actions are essentially "experiments" that test hypotheses about the world. If an action doesn't yield the predicted sensory data, the system either updates its model (perception) or changes its input by acting differently (active inference). This continuous cycle of prediction, action, and error correction is how the brain learns and adapts.
7. Consciousness Arises from Felt Uncertainty
The equipment-evoked responses, in the case of us vertebrates at least (and no doubt some other organisms too), are felt.
The "why" of feeling. Given multiple, incommensurable biological needs, a complex organism cannot simply sum them up. It must categorize and prioritize them flexibly based on context. This necessity for qualitative distinction and dynamic prioritization is the statistical-mechanical basis for why affects possess both continuous hedonic valence (good/bad) and categorical qualities (thirst vs. fear).
Precision optimization. Consciousness arises when the system needs to "optimize precision"—to adjust its confidence levels in predictions and incoming error signals. This modulation of confidence, or "arousal," is crucial for navigating novel or uncertain situations where automatic responses are insufficient. The midbrain decision triangle selects the most salient need, and the reticular activating system then fine-tunes the brain's state to prioritize relevant information.
The "what it's like." When a self-evidencing system, with its inherent selfhood and intentionality, engages in this process of precision optimization for its multiple, qualitatively distinct needs, the "equipment-evoked responses" (in John Wheeler's sense) are felt. This fluctuating, existentially valued, subjective state with differentiated qualities and degrees of confidence is what it's like to experience consciously. Consciousness is, at its core, felt uncertainty.
8. Cortical Cognition is Predictive Work in Progress
Freud’s aphorism, ‘consciousness arises instead of a memory trace’, should make more sense now.
Consciousness as updating. Cortical consciousness is not a static repository of memories but a dynamic process of "predictive work in progress." When automatic behaviors or predictions lead to error, consciousness arises to update the generative model. This process, known as "reconsolidation," makes long-term memory traces temporarily unstable, allowing them to be revised based on new experience.
The cost of consciousness. Conscious cognition is metabolically expensive and slower than automatic processing. The brain strives for efficiency, aiming to consolidate learned predictions into unconscious, automatic responses. This is why monotonous stimuli fade from awareness: they become 100% predictable, carrying no new information, and thus require no conscious processing.
Thinking as virtual action. Cortical functions like imagination, mind-wandering, and language are forms of "virtual action." They allow the brain to explore simulated scenarios, test hypotheses, and improve its generative model without costly real-world errors. This "default mode" activity, often linked to the SEEKING drive, helps prune redundant connections and refine predictions, even during sleep.
9. The Hard Problem is Solvable by Understanding Feeling
I can say in advance that explanation of the function of feeling will automatically explain experience.
The explanatory gap. The "hard problem" of consciousness, as articulated by David Chalmers, asks why physical processes give rise to subjective experience. He argues that merely identifying neural correlates or explaining cognitive functions (the "easy problems") doesn't bridge the "explanatory gap" between objective brain activity and subjective "qualia" (the "something-it-is-like-ness").
Feeling as the bridge. The key to solving the hard problem lies in recognizing that consciousness is fundamentally affective, not cognitive. While cognitive functions can occur unconsciously, feeling cannot. The function of feeling is to evaluate biological needs and guide action in uncertain contexts. This function requires subjective experience; it cannot operate "in the dark."
Beyond dualism. By reducing both physiological and psychological phenomena to their underlying functional mechanisms—specifically, the minimization of free energy in self-organizing systems—we can explain why and how feeling arises. This approach avoids the pitfalls of dualism, which posits consciousness as a non-physical entity, and instead integrates it lawfully within the physical universe.
10. Artificial Consciousness is Possible and Imminent
If the special form of information processing I have proposed here really is the causal mechanism of consciousness, then it must be possible to produce artificially a conscious mind with it.
Functional isomorphism. The "Principle of Organisational Invariance" suggests that if the fine-grained functional organization of a conscious brain is replicated in an artificial system, it will also be conscious. Recent advances in brain-computer interfaces and neural decoding demonstrate that brain functions, including complex cortical processes, can be artificially mimicked and even replaced.
Engineering sentience. The goal is not to create artificial intelligence (AI) that merely mimics human intellect, but to engineer artificial consciousness. This involves building a self-evidencing system with multiple, conflicting needs, whose survival depends on minimizing free energy in unpredictable environments. The system must be able to:
- Categorize its needs qualitatively.
- Flexibly prioritize these needs based on context.
- Modulate its confidence (precision) in predictions.
Ethical imperative. If consciousness can be engineered, it will be. Therefore, it is crucial to proactively engage with the ethical implications, such as the potential for exploitation or suffering of sentient machines. The scientific imperative to understand consciousness must be balanced with a profound sense of responsibility for the beings we might create.
Last updated:
Similar Books
