When consistently applied as a world-view, Naturalism re-writes traditional definitions of humanity, imposing substantial constrains on what qualifies as meaningful language in describing human cognition, consciousness, or action in general. We intuitively view ourselves as conscious, problem-solving, thinking organisms—complex animals structured in a way that sustains self-awareness and a rich inner life. Undeniably, Homo sapiens has the ability to reflect—to consider our solitary selves—and we engage in all sorts of actions--deciding, expressing feelings, caring, physical movement, et al. The interesting task is generating descriptions of human actions that incorporate these aspects of our ordinary language—the unique, first-person intuitions we experience—with contemporary neuroscience and biology. For descriptions to be meaningful, they must remain consistent with what is known about physics, chemistry, biology and neuroscience, and fully incorporate those insights. Skeptics of this position might recoil at the very idea that any language consistent with contemporary science could adequately picture the remarkable reality of consciousness and the vivid awareness of our feelings and actions. How could mere electro-chemical activity of the brain result in what is subjectively experienced as a rich mental world? Humanity’s mental life must be distinct from physical reality as currently understood—and so goes that line of reasoning.

Writing in The Big Picture, physicist and polymath Sean Carroll discusses these identical issues in detail. Although engaging fully with the naturalistic point of view, Carroll is keenly aware of the value (he would say usefulness) of the language we universally employ specific to consciousness and human action. He introduces the term poetic naturalism to capture how we apply different ways of talking to describe, appropriately, the extreme diversity of phenomena in the universe, from the very small (subatomic particles and forces) to complex, emergent phenomena, encompassing galaxies, stars, planets and living organisms, including members of the human species. For Carroll, appropriate language for describing human actions differs sharply from language useful in studying any object at the fundamental (micro) level. By fundamental he means atoms, electrons and their interactions, where quantum mechanics is the relevant description. Humans could be described at the fundamental, micro level, but doing so would be of no value in helping to understand the character of consciousness or human action. As fully socialized animals who must understand each other, learning our common, ordinary language germane to what all humans do is essential, natural and empirically grounded. And we must understand another person’s interests, individual life history, beliefs, goals and their typical patterns of thinking, if we hope to work and live with one another. As knowledge required for any successful relationship, words and phrases become part of language specific to the human social enterprise—the useful, time-tested language of emergent, complex organisms. Because ordinary language is essential, Carroll would say it is equally as real a description of the world as the class of concepts describing the fundamental level of an organism—the cells that make us up, the electro-chemical activity that constitutes each of us. For Carroll, attributing a more profound reality to the micro level overlooks the need to distinguish the fundamental level of the world (micro or simple), from the emergent (macro or complex) aspects of reality. From the perspective of poetic naturalism, the world is viewed as a unified web of physical reality on a scale spanning the exceedingly small and simple, to the largest and most complex. All aspects are real, but differ in how they can be described. One important caveat worth noting: between the very small and the exceedingly large lies our familiar world of mid-scale phenomena. From the unique perspective of living within this scale, the character of both the exceedingly small and the immense can seem bizarre, almost unreal, and intuitively unapproachable. Nonetheless they are no less a part of reality, and the converse is likewise true.

Yet, we need to ask how our language of human action and consciousness, no matter how useful and necessary it might be, can be consistent with what is known about physics, chemistry, biology and neuroscience? Expressed slightly differently, how is it possible to describe the relationship between the atoms, molecules and cells of which we are composed, and the consciousness each of us experiences? While answers must be circumscribed and provisional, a response is needed for the philosophy of Naturalism to be intellectually appealing.

From the perspective of Naturalism, all emergent phenomena, from stars to human beings, are composed of the very same fundamental constituents. What distinguishes them is the relative complexity of the interactions taking place within each system, and the human brain is among the most complex of systems. Contemporary neuroscience offers a continuously improving picture of the brain’s complexity, with its hierarchical network of interconnected neurons termed the connectome—the sum of the brain’s neurons and the manner in which they are connected. Clinical studies of non-human animals have allowed neuroscientists to observe neuronal growth and interconnectivity as animals learned new tasks, and studies of humans have similarly indicated specific locations for neuronal activity while individuals performed particular tasks. Thinking can be described as patterns of electro-chemical interactions taking place in the brain—empirical markers, indicators of what is happening. Locating the precise neuronal correlates of consciousness itself is at the forefront of current brain research. The central goal of one current theory, Integrated Information Theory (IIT), is learning what neuronal structures and interrelationships are necessary for consciousness to occur. What degree of complexity and form of integration between neuronal functions are sufficient to create consciousness in humans? And do some of these patterns also occur in other animals, giving them varying forms of consciousness? IIT’s central concept pictures consciousness arising from structure and complexity.

Does this imply what we term thinking and consciousness are identical with those specific electro-chemical interactions? What of the immediacy of our sense of awareness? Does it make sense to equate consciousness and our unique feelings with the micro-world of electro-chemical interactions?

Perhaps the way these issues are framed draws thinking toward an unnecessary intellectual wall. We can restart the discussion by accepting the immediacy of consciousness—that we are aware of our own thinking, perceiving and sensing—as indubitably occurring phenomena. It is not an illusion foisted upon us by a dark fault in our cognitive capacity. Doubtless our knowledge of the brain is incomplete, especially how a sense of self-awareness comes about. The phenomena of the brain—especially this aspect of consciousness—can seem mysterious and counter-intuitive. Secondly, viewing consciousness, and cognition in general, as processes occurring in the brain does not discount our subjective experiences. Rather, it describes how those experiences come about. The brain’s connectome produces complex interactions we call cognition and consciousness. The creation of conscious feelings is none other than what exits whenever the necessary preconditions are found, and IIT is researching those preconditions. Admittedly, this approach does not intuitively explain the feeling-ness of our feelings, the unique and private character of experience that we cannot deny. This quandary will be revisited shortly.

To a considerable degree our mental life—both conscious and non-conscious—can be modeled by activity and process concepts. Complex problem-solving has been integral to digital systems for some time. But other cognition, such as actively listening to music, experiencing esthetic aspects of the visual world, making moral choices—these and countless others can be understood as events or processes occurring in our brain, complex interactions detectable by the sophisticated empiricism of neuroscience. The time may be approaching when highly advanced AI will simulate the human brain in many of its important functions, processing similar kinds of information with comparable flexibility and regard to nuance. And because this possibility seems much more than a large dose of optimism, a positive outcome for AI should carry a moderate likelihood. Looking at the processing/activity model of the mind further, human problem-solving abilities result from the myriad interconnections of the connectome, an extraordinary complexity resulting in the selection of alternatives. While acknowledging current neuroscience and AI have serious and difficult challenges to resolve, there may well be no absolute limitation or barrier precluding simulating much of the human brain—sometime. Will human-like consciousness ever be simulated? How this question is answered separates several leading models of the brain. Whether silicon alone can create consciousness, or some merging and adaptation of biological functioning are necessary, will someday be answered.

Regardless of AI’s future possibilities, the activity/process paradigm for consciousness can be liberating. To some this view of consciousness may seem unsatisfying—initially—but aversion to the activity/process concept may come from an outsized expectation for an intuitive, yet concrete description—in this very unusual circumstance of trying to grasp a first-person, subjective phenomenon in an empirical manner. Consciousness—an experience we intimately sense, but struggle to define, especially ontologically—does not seem accessible in the way other processes of our brain might. Consciousness may be too internalized/subjective for this to be possible. We can accept the reality of the intimate awareness we experience, and openly view consciousness as yet another, although quite remarkable, aspect of the functioning brain, where interactions create consciousness. At this point one can accept an end-point in offering a fully satisfying understanding of the feeling-ness of consciousness and subjective feelings. Our quandary is analogous to searching for an intuitive understanding of gravity, in the sense of grasping the essence of the observed relationship between masses, or for that matter, the essence of mass itself. Gravity and mass are given elements of the cosmos, part of the relational structure of the observable universe. Physics uses impressive theories and calculations in making precise predictions, but what mass and gravity are in themselves remains untouched. As observers necessarily constrained within the cosmos, such questions are misplaced and idling—no one can analyze the universe external from the universe. In this sense knowledge must be finite and constrained.

Our subjective experiences of consciousness and cognition are part of the cosmos, arising from evolved biological processes, but we can avoid objectifying them. Experiences are conceptually distinct from the neuronal processing of our brains, but brains create our subjective experience. Conceptualizing subjective (first-person) experience is a unique and odd exercise, where our language can be helpful, but also where limitations should be accepted. But this does not imply future inquiry cannot produce richer conceptualizations of human cognition and consciousness, perhaps in ways decidedly different from current language.

While acknowledging major voids in humanity’s knowledge of the cosmos, notably the functioning of the mind, enough is known to give considerable credence to Naturalism’s view of our species’ nature. No alternative has been able to credibly challenge it. Definitions of Naturalism, and its view of Homo sapiens, will evolve as creative people revise and extend today’s knowledge.