Since the time of the Pre-Socratics, natural philosophy has struggled with the nature of human consciousness, and the issue remains an acute philosophical and scientific quandary. We ask by what processes consciousness could have arisen, and whether neural processes themselves could provide a fully satisfactory description of its origin. And all these issues are imbedded in the more general question of its place, as a phenomenon, within the universe at large. The challenges and complexity of understanding consciousness continue to test humanity’s cognitive ability, but its enigmatic character could become less intellectually frustrating as inquiry re-thinks current perspectives, and considers the likelihood of epistemological constraints.

This essay looks at several differing, yet related, contemporary conceptions of the origin of consciousness. They share the fundamental assumption of consciousness as a defining characteristic of human existence, giving us the ability to experience ourselves and the surrounding world, an awareness that includes a sense of self and personal agency. Consciousness gives us the richness of our phenomenal experiences of the external world, as well as our feelings, mental images, memory, thought and language. All our experiences are subsumed under this single word. An interesting and important question is whether consciousness, in some currently unknown form, could be ascribed to non-biological complex systems. Without doubt there is conceptual richness—and fascination—imbedded in open-ended discussions of consciousness.

A widely-held, fully naturalistic conception views human consciousness as the natural evolutionary consequence of biological adaptations of the brain and nervous system. Current science describes the bio-physical processes underlying adaptation with a high degree of confidence. But for this scenario to carry us all the way to human consciousness, a crucial assumption must be added: consciousness can be understood as a wholly emergent phenomenon, and, at least in principle, fully described through electro-chemical processes, and consistent with present-day and/or future iterations of science. To say that consciousness is emergent implies it develops only from complex processes, and as a causal effect is completely dependent upon those causal antecedents. This wholly naturalistic view relies on conceiving the neural system’s extreme complexity as sufficient support for proposing physical processes, alone, can create the immediacy and richness of first-person conscious experiences. Naturalism views the neural networks in the brain as sharing systemic unity—enhancing further complexity yet achieving neural harmony—creating the emergent phenomenon of consciousness. For naturalism, the concept and phrase “emergence from neural complexity” stands as a useful descriptor awaiting more precisely expressed causal relationships. Those attracted to naturalism use the term “emergence” with considerable confidence, identifying the source of our experiences as the evolved human brain.

A significant appeal of naturalism is how seamlessly non-human animals fit into a “consciousness spectrum.” Few pet owners would deny that their companions display traits so very similar to our own—emotions, attention and feelings. Yes, we differ, but the continuum between ourselves and other animals seems fully grounded in our shared world.

In arguing against naturalism, philosophers have frequently remarked with genuine dismay, “how can ordinary physical processes possibly create the immediacy and subjectivity of conscious experience in humans, a phenomenon so very mental, so non-physical?” Naturalists often respond “this is the way things seem to be, as far as we know. Extreme complexity creating what may initially appear inexplicable. Complexity is the best explanation to date.” Much the same could be said about our use of the word “gravity,” where we have no clear, intuitive grasp of the essential nature of gravitons and gravitational fields, yet physics makes precise predictions of gravitational phenomena. This is not to say naturalist’s use of the phase “extreme complexity” brings the discussion to an end, or that human consciousness has lost all its enigmatic reputation. (for an earlier discussion of these issues, see my 5-20-22 essay “Making Sense of Consciousness—Quandaries Over Complex Systems”).

A second, and intriguing conception of consciousness, does not deny the facts of the biological adaptations of brains and nervous systems through natural selection, but offers a significant twist to the evolutionary story. The physicist and mathematician Roger Penrose has proposed consciousness did not emerge, secondarily, and in an evolutionary sense, through conventional physical processes. Rather, consciousness results from “discrete physical events that have aways existed in the universe in a proto-conscious state, and acted on by physical laws not yet fully understood” (paraphrased from Penrose). Penrose continues “Biology evolved a mechanism to orchestrate such events and couple them to neuronal activity, resulting in consciousness.” Penrose’s fuller theory is complex and far beyond the scope of this essay, but his most interesting idea describes consciousness as an “intrinsic feature of the action of the universe.” This contrasts with naturalism’s claim that human consciousness eventually emerged by means of the complexity of neural systems, and hence, not fundamental to the universe in the sense the subatomic realm is fundamental, or intrinsic. Penrose views his “proto-conscience states” as fundamental, suggesting a drift toward a form of pan-psychism. Some view pan-psychism as attractive because it provides a conceptual bridge, of sorts, from the physical to the “mental” and hence consciousness. Later we will return to this issue, and examine the words “intrinsic” and “fundamental” for their usefulness in discussing consciousness.

Recent research in the rapidly growing field of Basal Cognition presents a more empirically grounded approach in considering both Penrose’s conceptual model and naturalism’s emphasis on the essential role of complexity. Basal Cognition studies have focused on very small, multi-cellular creatures, so primitive to be without brains, yet exhibiting lower-level cognition with primitive memory and learning capabilities. This lower-level cognition—or proto-intelligence—occurs without the clusters of neurons found in slightly higher-level animal’s primitive brains, and use only subtle changes in electric fields within simple, non-neural cell groupings. Researchers Michael Levin and Pamela Lyons (see Scientific American 2-24) describe a framework where cognition builds from very simple beginnings, with surprisingly sophisticated cognition occurring near the lower end of life’s complexity spectrum. While Basal Cognition studies focus on early-stage cognition, such as primitive intelligence and learning—but not consciousness as usually understood—the concept of very early-stage cellular cognition fits the naturalist assumption of the continuity from simple to complex organisms—from the action of subtle changes in electrical fields in simple cellular groups, to the highly complex neural systems of the human brain. Assuming the work of Levin, Lyons and others in Basal Cognition becomes an accepted standard in biology, the naturalist framework of continuity and similarity between simple and complex systems becomes highly likely, and difficult to dismiss. Philosophically, highly developed brains, such as the human brain, lose any semblance of exceptionalism. Doubtless our brains are remarkable, but differing only in degrees of complexity and capability to those of other animals.

Placing human consciousness aside temporarily, naturalism’s description of the continuity between Basal Cognition and the highly developed functioning of the human brain, strongly suggests we can consider intelligence, as a cognitive process in humans, in principle fully describable by science. This would be true to the degree that electro-chemical processes are the basis for everything, including advanced thinking (whether carbon or silicon-based) and ultimately consistent with and derivable from the subatomic realm. While the advanced cognitive processes taking place in the human brain are not fully understood, the incompleteness of our knowledge does not entail, or even strongly suggest, the existence of unknown sets of physical laws. We gain simplicity and consistency by extending open-ended research using current science, yet being vigilant for anomalies that could upend our preconceptions. Penrose’s work reflects much of this approach, but his drift toward pan-psychism seems premature and overly speculative.

When Penrose uses the word “intrinsic” in describing consciousness, as in “consciousness plays an intrinsic role in the universe” and in his phrase “proto-conscious states,” he is presenting a conceptual tool for understanding the character of consciousness as inherent—perhaps even necessary—to the universe. He theorizes consciousness is not an evolutionary accident, but fundamental to what exists. Penrose may also assume his language can begin to provide an intuitive grasp of consciousness, mitigating some of its enigmatic character. I question whether this is successful. Whether we focus on intrinsic “proto conscious states” or naturalism’s “emergence,” we cannot intuitively grasp how events—processes—create the subjective reality of conscious awareness. Penrose’s “proto conscious states” only place the enigma farther back in time. Naturalism’s “emergence” assumes specific stages of complexity can create primitive Basal Cognition, with the sophisticated cognition and consciousness of humans possible from advanced complexity. Unsurprisingly, the precise processes leading to the emergence of human consciousness are unknown.

Penrose’s conception of consciousness is intriguing, with his blend of neuroscience, quantum biology, mathematics and cosmology—an original thinking polymath. But I return to his reluctance—and other creative thinkers’ reluctance—to embrace the considerable likelihood that consciousness is an emergent phenomenon. The idea of emergence is remarkably consilient with so much of contemporary science. But there remains the seeming enigma of consciousness. Consciousness has always been a wondrous and rich web of phenomena—those experiences, feelings and self-awareness that create the uniqueness of each person. Its immediacy and subjectivity are not readily conceived as the result of physical phenomena. An important categorical distinction needs to be made between two very different issues. What may be possible for us to know are the precise neural processes leading to consciousness. This may occur through further advances in neuroscience, perhaps including insights from computer science. A second, very different issue is removing barriers to accepting the possibility of neural processes, alone, creating the subjective feeling of awareness. We should place in abeyance the idea that emergence must be false, simply because it does not mirror a very questionable belief in the singular uniqueness of human consciousness—the dubious idea of human exceptionalism. I we can do so, our conceptual angst about consciousness is likely to subside, with our intellectual prowess directed toward more fruitful inquiry.