The View From Inside: How Mind Emerged From Mindless Matter

“Conscious experience is at once the most familiar thing in the world and the most mysterious. There is nothing we know about more directly than consciousness, but it is far from clear how to reconcile it with everything else we know. Why does it exist? What does it do? How could it possibly arise from lumpy gray matter?” —DAVID J. CHALMERS, The Conscious Mind: In Search of a Fundamental Theory (1996)

The philosopher Thomas Nagel famously stated that “an organism has conscious mental states if and only if there is something that it is like to be that organism—something it is like for the organism.”¹

The mystery of subjective experience, also known as the “hard problem of consciousness,” concerns how and why we have such experiences at all. The subjective, first-person experiences of sensory and mental phenomena, such as the striking redness of a rose or the tang of a lemon on the tongue, are referred to as “qualia.” The ultimate quest of neuroscience is to explain how qualia are produced by the brain and to explain how it is that our brain produces a distinct sense of self—an entity experiencing those qualia, possessing also agency, a coherent sense of stability and continuity, and a personal narrative. 

Across history, most people have found it extremely difficult to conceive of conscious experience as the product of physical processes, often viewing the mind or soul as distinct from the body—humans are natural-born dualists.² People naturally hope—indeed are often convinced—that their consciousness is not extinguished by the death of the brain. Furthermore, we find our own subjective perceptions arrestingly compelling, failing to understand or accept how unreliable our minds are in many situations. Taken together, these natural human tendencies account for the widespread human belief in spirits, afterlives, and other forms of postmortem existence. The practice of burying the dead with tools, ornaments, and other goods among early Homo sapiens and possibly Neanderthals suggests that such ideas may have very deep roots. 

We are also strongly biased to see purpose everywhere, including in the universe itself. We long to feel that we are here for a special, intended reason.³ It is therefore unsurprising that theories portraying consciousness as fundamental to reality and pervading the universe have gained renewed attention and popularity in recent years. 

Despite these deep intuitive pulls, most scientifically credible theories of consciousness today are materialist (physicalist)—and for good reason: every other phenomenon once thought to require something beyond physical explanation has eventually yielded to one. Within that materialist frame, there are a number of competing theories at this still early stage in the science of consciousness. 

Leading Theories and Other Strong Contenders 

In a five-part series that I wrote for Psychology Today on the leading theories of consciousness,⁴ I described the specifics of the major candidate theories, drawing from an influential 2022 Nature Reviews Neuroscience paper by Anil Seth and Timothy Bayne, outlining the four leading theories selected by the authors: 

1. Higher-Order Theories 
2. Global Workspace Theories and Global Neuronal Workspace Theory 
3. Integrated Information Theory 
4. Re-entry and Predictive Processing Theories 

These are indeed all strong contenders—perhaps more or less equally—but all four have weaknesses. For one thing, there is an insufficient emphasis on evolution.⁵ And, these theories variably—and often insufficiently—integrate attention, learning, and affect. There are other strong contenders that, I think, more satisfactorily address these elements, which I address in this article. 

Theories of consciousness must be firmly rooted in evolutionary biology.

It has been famously said that nothing in biology makes sense except in the light of evolution,⁶ yet consciousness seems so different from other biological functions—thoughts and feelings seem ethereal and untethered from anything physical. Self-awareness seems like a phenomenon utterly divorced from anything that could possibly be produced by cells comprised of physical particles. 

As soon as the first cell evolved there was an inside and an outside, and therefore the beginnings of a subjective-objective divide between the body and the outside world.

People used to think of life itself that way, too. Living things were believed to possess some sort of animating essence—élan vital—that accounted for their difference from inanimate matter. People could not imagine how the same material particles that comprise inanimate matter could be arranged in such a way as to make something alive without adding a special, mysterious nonmaterial essence. No one worries about that now because we know how biological processes give rise to living tissue and organisms. 

Likewise, we have long known from clinical neurology and from my own field, clinical psychiatry, that disruption, disassembly, or enhancement of brain circuitry—subtle or major—can radically alter any aspect of the mind. And yet the mystery of how exactly the brain produces consciousness remains unexplained. How does this emerge from an approximately three-pound organ with the consistency of tofu?⁷ How can a purely physical thing feel like something? The answer is to be found in an evolutionary process of emergence. 

In the Beginning 

Let’s go back nearly four billion years, long before animals had brains or even a nervous system, back to simple single-celled organisms like bacteria. This is not to suggest that simple unicellular organisms possessed consciousness, but they possessed its building blocks: behavior and the precursors of sensing, learning, and memory. 

Properly understood, behavior, detection (sensing), learning, and memory do not require a nervous system. Nervous systems evolved later, followed by central nervous systems, enabling greater coordination and behavioral flexibility. At the most basic level, responses to stimuli can be characterized as either approach (e.g., to a nutrient) or withdrawal (from something noxious or dangerous). Behaviors in more complex organisms are basically just more elaborate versions of this. In fact, some of the genes involved in learning are the same in complex animals as in protozoa, which are very primitive single-celled organisms lacking a nervous system and which evolved at least 1.5 billion years ago.⁸ Nervous systems, and especially more complex brains, ultimately enabled organisms to regulate their behavioral responses and internal physiological states through such capacities as: 

prediction, planning, delaying or inhibiting, remembering (storing patterns of information from past encounters), learning (modifying behavior through conditioning, or through remembering previous outcomes, or in higher animals through imitation), and weighing different behavioral responses (comparing), and evaluating outcomes of behavior. 

Consciousness probably evolved to enable nonreflexive behavior. By allowing organisms to maintain and manipulate internally generated representations detached from the immediate sensory environment, consciousness supports delayed responses, planning, mental simulation, and flexible action.⁹ And even in humans, most behavior is carried out by nonconscious processes. Here are some of the milestones in the evolution of cell signaling, nervous systems, and consciousness: 

• Primitive cell signaling began 3.5 to 3.8 billion years ago in the first single-celled organisms (prokaryotes—bacteria and archaea—which reproduce asexually by simple cell division); followed around two billion years ago by larger, relatively more complex single-celled organisms (eukaryotes, such as protozoa; eukaryotes contain a nucleus and organelles and reproduce sexually, which introduces more genetic diversity). 
• Neurons formed diffuse (noncentralized) nerve nets in multicellular organisms (in hydra and jellyfish-like creatures) around 600–700 million years ago. 
• Precursors of centralized nervous systems in small, primitive worm-like creatures in the Cambrian period, began almost 550 million years ago. 
• More richly interconnected central nervous systems in more complex invertebrates and vertebrates appeared from the Cambrian period onward. 
• Progressively more sophisticated capacities of brains emerged in larger animals (fish, amphibians, reptiles, birds, mammals, and cephalopods) in the last few hundred million years, enabling them to form internal representations of their environment and of themselves (i.e., maps or models of their external environment and of their own body and actions), with correspondingly more flexible behaviors. 
• Many mammals and some birds developed a more advanced form of cognition, involving the capacity to form and manipulate complex internal models. Higher mammals may have developed a basic sense of self. Primates, especially humans, developed the ability to internally represent their own thinking patterns more reflectively. Probably only humans developed the ability to be aware of being aware, reflecting on their own existence as a conscious being. 

It’s worth noting that subjectivity is built into the very nature of life: as soon as the first cell evolved, there was an inside and an outside, and therefore the beginnings of a subjective-objective divide between the body and the outside world. Subjective experience is inaccessible to external observers. 

The Origins of Purpose and Meaning 

Purpose emerged with life itself, long before consciousness evolved. Living organisms act in ways that promote survival and reproduction, whether or not they possess consciousness. Consciousness evolved later as an adaptation that allowed more flexible control of behavior in pursuit of those biological aims. 

The mind is a kind of map.

Although a simple bacterium has no consciousness, it can nevertheless detect glucose in its environment, move toward it, and ingest it to convert it into energy. In a minimal biological sense, a bacterium behaves as an intentional agent, and it makes an “effort” to achieve its purpose or aim. An intentional agent can interpret patterns as being about something of value in its environment—glucose, for instance, signifies or means energy to the bacterium.¹⁰ An agent forms an internal representation of things in its environment (in this case, glucose) so as to recognize, respond to, and process that thing. These processes are entirely mechanistic, analogous to a lock-and-key interaction. The internal representation has meaning and value to the organism, in the sense that it represents something good or bad for the organism—promoting or impeding its survival and propagation. 

Thought and Information 

A thought is a representation of something, a likeness, a thing that depicts another thing by having characteristics that correspond to it. A picture, image, imprint, or mold of an object is a representation of that object, as is a map. The mind is a kind of map. The brain—and its functional product, the mind—evolved as a map of the body’s relation to its external environment. Our thoughts are maps representing things that our brains have either perceived with our senses, felt with our emotions, or formed as an action plan. 

Information requires a physical medium. Whether encoded in ink on paper, electronic states in a computer, or patterns of neural activity in a brain, information cannot exist independently of a physical representation. Thoughts, memories, and mental representations are therefore inseparable from their underlying neural substrate.¹¹ Information acquires meaning from its correspondence to actual things in the world and to other information. 

Internal representations are models of the body and the world, physically encoded in neural activity and connectivity. They have a relational nature to the reality they map; they are direct correlations to physical things. They arise when sensory systems transform physical signals—light (photons), sound (air vibrations), touch (mechanical stimuli), smell (chemicals), and signals from the body itself—into patterns of neural information. 

Thus, the brain forms models of the world and of itself in relation to the world. Through learning and experience, these networks become organized into increasingly sophisticated models that guide perception, memory, prediction, and behavior. The ability to form internal representations is a key ingredient of consciousness.¹²

Memory, Learning, and Emotion 

Brains evolved the ability to store salient representations, retrieve them later, integrate them with new information, and update them through experience. 

Memories and concepts are encoded in distributed networks spanning many brain regions. Just as no single pixel contains an image, no single neuron contains a memory or concept. Furthermore, individual neurons participate in numerous overlapping representations, allowing memories to be interconnected and associated with one another. This also helps explain how the brain can store vast amounts of information while flexibly integrating new experiences with old ones. 

In neuroscience, an “engram” refers to the physical trace of a memory. When part of the network is reactivated by a cue or reminder, the broader pattern can be reconstructed, allowing the memory to be recalled. 

Because the brain’s model of awareness lacks access to its own billions of neurons, synapses, and electrochemical processes, awareness appears to the brain itself to be a nonphysical essence rather than a biological process.

Learning is based on establishing correlations between things. Behavioral conditioning occurs through rewards and consequences reinforcing or weakening those associations. 

According to an elegant theory by Simona Ginsburg and Eva Jablonka, learning may actually be the fundamental driver of the evolution of consciousness:¹³ “The evolution of learning and the evolution of consciousness are intimately linked, even entangled.”¹⁴ Their theory proposes that a form of associative learning or conditioning that they call “unlimited associative learning” (UAL) is an evolutionary marker of simple consciousness.^15, 16 Before the evolution of UAL, organisms tended to respond to stimuli reflexively. After UAL, they can evaluate alternative responses before acting. This transforms the adaptive landscape. 

Complex animals possess an inherent drive to learn, driven by curiosity and what neuroscientist Jaak Panksepp termed the “SEEKING” system—one of several basic emotional circuits he identified as evolutionarily ancient and shared across mammals.¹⁷

Positive and negative reinforcement obtained through associative learning gives experiences positive or negative valence, laying the foundation for affect. Thus, brains assign value to stimuli—goodness or badness. This forms the basis for the evolution of feeling and emotion, and the fuel for motivation and goal-directedness.¹⁸ Underlying all of this is homeostasis: the maintenance of physiological stability is central to affect. 

In mammals, the evaluative aspect of meaning is supported by interactions between distributed cortical representations and subcortical systems involved in affect and action, which assign significance to patterns based on their relevance for the organism’s needs and goals. 

Understanding emotions, then, may be fundamental to understanding subjective experience. As the neuropsychologist Mark Solms notes, unlike other forms of information processing, you can’t have a feeling without feeling it.¹⁹

Predictions and Expectations 

Many neuroscientists view the brain as a prediction machine. Rather than passively receiving sensory information, it continually generates expectations about the world and updates them in response to incoming evidence. Mental representations are central to this process. 

Anil Seth’s predictive-processing account describes conscious experiences as “controlled hallucinations” generated by the brain’s attempts to predict and regulate both the external world and the body’s internal state. According to Seth, conscious experience is closely tied to these predictive processes, particularly those involved in maintaining the body’s physiological stability through anticipatory regulation.²⁰

It’s worth noting that subjectivity is built into the very nature of life: as soon as the first cell evolved there was an inside and an outside.

Related ideas are captured by Karl Friston’s Free Energy Principle, which proposes that organisms continually act to reduce uncertainty by improving their predictions and bringing sensory inputs into alignment with those predictions. Through this process, brains become increasingly effective at navigating their environments.²¹

Cognition, Intelligence, and Consciousness 

Cognition refers to the mental processes involved in acquiring, processing, storing, and using information; intelligence is how effectively those processes are deployed. Consciousness, by contrast, concerns subjective experience. 

Joseph LeDoux defines cognition as the ability to form internal representations and use them to guide behavior. Even relatively simple animals can act on stored representations of food, danger, or other biologically significant stimuli, rather than merely responding reflexively to what is immediately present. Mammals and some birds appear capable of a more advanced form of cognition, using internal models to simulate or imagine potential outcomes, evaluate alternatives, and guide flexible, goal-directed behavior. This capacity for prediction and planning greatly expands behavioral control and adaptability. 

Where does this happen in the brain? There is a longstanding debate over whether consciousness arises primarily from cortical or subcortical brain systems. Most current theories emphasize the cerebral cortex, whereas others argue that the foundations of consciousness lie in evolutionarily older brainstem and subcortical circuits involved in arousal, emotion, and motivation. 

It feels like something to have a thought and to be a self because we are that information. The sense of self is built from self-representations.

A growing middle-ground view holds that subcortical systems generate arousal, motivation, valence, and perhaps rudimentary feelings, while cortical systems elaborate these states into richer perceptual, cognitive, and self-reflective forms of conscious experience. The debate has important implications for animal consciousness, influencing whether consciousness is viewed as largely restricted to animals with complex forebrains, such as mammals and birds, or as extending more broadly across vertebrates and perhaps even some invertebrates. 

Nonconscious Cognitive Processes 

Joseph LeDoux emphasizes the “cognitive unconscious”—the nonconscious cognitive processes that allow us to control complex behaviors without having to call upon consciousness. Most of our routine behavior, and even quite complex behavior, is carried out by nonconscious cognitive processes—everyday movements, much of language processing, tasks like driving a car for an experienced driver, and so on. Many actions can be “delegated” to nonconscious cognitive processes, which reduces the cognitive load on conscious information processing. But conscious information processing enables greater behavioral control and more flexible responses to stimuli than do nonconscious cognitive processes. 

Although many nonconscious processes depend on evolutionarily older subcortical systems, nonconscious cognition occurs throughout the brain. Indeed, most of the brain’s cognitive work—including much of its cortical processing—takes place outside conscious awareness. 

Complex, Abstract Representations 

Whether conscious or not, all of this cognitive work depends on internal representations. At a basic level, these are simply sensory images. But what about abstract thought? Complex brains form representations of representations—hierarchies or ladders of representations built upon one another. Abstract mental concepts are constructed as higher-order representations from symbolic, analogous correspondences to physical things; they are still assembled, at bottom, from the building blocks of sensory perceptions and movements, upon which all other thoughts are built. 

Abstract thoughts are, in essence, still maps corresponding to the external environment and the individual’s position in it. Like maps (and all representations), they preserve relationships that correspond to features of the world. One thing reminds us of another because of some similar feature. Douglas Hofstadter and Emmanuel Sander argue that making analogies is a fundamental mechanism of thought. Our brains continually map similarities between new and familiar situations, allowing past experience to guide present understanding. Language reflects this process: we routinely describe abstract concepts in physical terms, speaking of “bright” ideas, “deep” problems, or “bitter” remarks. On this view, abstract thinking is built from increasingly sophisticated representations ultimately grounded in sensory experience.²²

Self-Representations and Self-Awareness 

Antonio Damasio proposes a model for how the self emerges in gradations, in organisms of increasing evolutionary complexity—a simple organism develops a rudimentary form of “self-awareness” by forming a map of its body and its position in the physical space it occupies. Damasio calls the most basic representation of self the protoself—a nonconscious precursor to self-awareness that may exist even in relatively simple organisms. 

It’s a very basic level of awareness: neural patterns mapping the body’s physical structure.²³ These self-representations combine with affect (feeling) to provide a sense of ownership of the body and of perception, a feeling of presence and agency—the sense of being an entity that is doing the experiencing. A feedback loop of the brain’s modeling, predicting, and controlling of the body’s internal state and actions reinforces the sense of self.²⁴

This is not unlike Douglas Hofstadter’s idea of self-reference and formal rules,²⁵ in which the sense of self emerges from recursive self-representations—what he calls a “strange loop”:²⁶ the brain forming models of its own modeling processes.²⁷

We are the sum of all our complex, dynamically interconnected brain networks.

Thus, it feels like something to have a thought and to be a self because we are that information. The sense of self is built from self-representations. We are the sum of all our complex, dynamically interconnected brain networks. We are composed of a lifetime of remembered experiences, knowledge, learned behaviors, and habits. We are all of that information, physically embodied in patterns of neural connectivity. 

Along these lines, Michael Graziano proposes that the brain evolved a simplified internal model—or schema—of its own attentional processes, much as it maintains a model of the body. This schema is a simplified “cartoonish” representation that depicts an internal capacity for awareness without representing the underlying neural mechanisms that generate it.²⁸

Because the brain’s model of awareness lacks access to its own billions of neurons, synapses, and electrochemical processes, awareness appears to the brain itself to be a nonphysical essence rather than a biological process. According to Graziano, this helps explain why people so naturally experience consciousness as something immaterial.²⁹

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Consciousness remains one of the deepest mysteries in science. We still do not know precisely how neural activity gives rise to subjective experience, nor why there is “something it is like” to be a conscious organism. 

Yet the mystery no longer appears quite as impenetrable as it once did. Modern neuroscience increasingly points toward a gradual evolutionary story. The building blocks of consciousness can be seen to emerge step by step: sensing, learning, memory, internal representations, prediction, valuation, feeling, self-modeling, and, in humans, language and reflective self-awareness. 

Living organisms have an inside and an outside. Central nervous systems evolved to model, predict, and control both as fully as possible. As brains became more complex, animals developed increasingly sophisticated representations and models of themselves and their environment. Conscious experience is inextricably rooted in how the self and the world are represented from the internal perspective of a living creature—a perspective that is simply inaccessible to, and can only be inferred by, an external observer.