Central to a person’s world-view is how they conceive our species’ place in the Cosmos. What is the nature of human-kind? Are we cognitively advanced animals on a continuum with other species, or something categorically different? Whether or not humans—in all aspects—are placed on a biological continuum becomes a decisive juncture. And when such decision-points vary sharply between individuals and cultural groups, earnest, if not volatile, interactions happen. Engaging others whose world-views sharply to ours becomes a complex brew of stimulation, challenge and empathy. And as some have experienced, Naturalism’s central ideas can be disconcerting to those steeped in traditional beliefs, and even viewed as inimical to stable and civilized societies.

If Naturalism is to become the dominant world-view, its proponents must weave a persuasive narrative, integrating intellectual appeal with emotional resonance, coupled with credible arguments supporting Naturalism’s compatibility with flourishing and sustainable societies.

THEMES IN CONTEMPORARY NATURALISM

Naturalism will be described in the broadest way, sidestepping its many philosophical points of divergence. Although at risk of postponing interesting issues, Naturalism’s overall relationship to competing world-views will become particularly clear.

Naturalism’s central thesis: the natural world—the world understood through science-based inquiry—exhausts accessible reality. There is one world, the natural world; there is no separate supernatural, spiritual or divine realm. There are not two differing planes of possible experience, the natural and the supernatural, each accessible by two different kind of knowing, where one uses problem solving, intuition and observation, and the other arises from revelation and faith. Life in general, as well as human consciousness, arise from matter and energy; what distinguishes biological systems is their remarkable complexity, and nothing else. The natural world is a continuum from micro to macro, from simplicity to complexity. If the aphoristic style of the thesis appears over-reaching, or simply false to some, the following narrative includes subtleties and clarifications that may be of value to skeptics of Naturalism.

Humans describe themselves using action-laden language: we are thinking, creating, caring, adapting, decision-making and goal-seeking entities—we are alive and dynamic. Humans “do things”, we perform actions and we share a capacity for moral sensibilities. And all the descriptive language just used remains meaningful and useful within a Naturalistic thesis. Contemporary Naturalism does not reject the ordinary language employed in talking about ourselves and others. But for this conclusion to make sense requires fully embracing an Evolutionary point of view.

Neo-Darwinism (the Modern Synthesis in biology) describes how complex biological systems evolved from much simpler predecessors. Although presently no comprehensive, consensus-supported theory describes how primitive life forms developed from their constituent chemicals—the emergence of what we call life. There are no reasons to conclude this could not be accomplished over the next few decades. The quest for knowledge is a powerful human trait, and ever since the Scientific Revolution our understanding of the world—including the nature of our own species—has been strongly progressive. Earlier explanatory theories have been superseded by more comprehensive ones as consecutive iterations more closely approximate the character of the world around us. Probing and creative inquiry will continue as long as intelligent beings exist, whether human or otherwise. And given the historical record of science-based inquiry and its post-modern global development, there is greater confidence in its continued success than any serious retrenchment. This degree of confidence makes it reasonable to assume the biological disciplines will develop a comprehensive description of living systems from the most primitive and fundamental, to the most complex animals—including humans—an evolutionary continuum from simple to exceedingly complex. Life’s origins will be understood.

Throughout the history of both philosophy and science, the phenomenon of human consciousness has appeared particularly enigmatic. We intuitively grasp the reality of our own consciousness, but success in accounting for consciousness (our subjective experience) has been considered elusive--what the philosopher David Chalmers has labeled the “hard problem”. How can our subjective experience—our feelings of sadness, the sensation of vibrant color, or the experience of awe as we view a starry night and imagine the expanse of the Universe—arise from the complex electro-chemical interconnections of our brain’s neurons? How can what we commonly label as our mind emerge from nothing but the physical interactions of our brain, the electro-chemical changes described at the simplest level by chemistry and physics? Because the human brain is inordinately complex, an account of its operations must be tied to all the implications of that complexity, asking whether a fully naturalistic point of view can make sense.

Complexity as a word carries wide-ranging implications. When systems are compared, especially mechanical systems with variations in the number of parts and their relationships, “simple” and “complex” are easily and unambiguously applied. Recently the discipline of network neuroscience has focused on describing what complexity can mean when applied to the brain’s network of interconnections. In recent decades neuroscience has established that particular regions of the brain carry out defined functions, such as vision, motor skills, emotions, etc. Network neuroscience is now learning how each region of the brain is imbedded in a unified network of massive complexity, enabling humans to carry out their normal cognitive functions—decision-making, problem-solving, remembering, including general consciousness. In this case “complexity” labels a physical structure dissimilar in character to what we ordinarily assume. And the precise character of this neural structure—with slight variations specific to each human being—makes each of us fully human. Network neuroscience’s conception of complexity has differing implications, or meaning, from our ordinary use of the word. A concept is employed that initially can seem puzzling: subjective experiences, indeed consciousness, are simply products of neural processing. Such massive complexity can be envisioned, analogically, as the biological correlate to phase changes seen in chemistry and physics. Different degrees of neural complexity will lead to strikingly varying levels of cognitive awareness—from more simple organisms to highly complex humans—where the extremes along an uneven continuum share some traits but not all. From this perspective, consciousness is an evolved aspect of the human species. This evolutionary point of view is consistent with other animals having a degree of self-awareness, while not identical to ours. No one should be surprised if future research confirms this. A currently leading theory of consciousness, Integrated Information Theory (IIT), measures the degree to which information in a neural system is both differentiated into regions and unified as a whole—a promising perspective in describing the uniqueness of neural complexity. IIT also suggests other species with suitably organized neural system would share aspects of consciousness.

A common conceptual miss-match when considering consciousness is an intellectual bias toward objectifying the phenomenon. Neuroscience does not conceptualize consciousness as a module or region of the brain, but rather a process taking place within the brain’s highly integrated structure. Our experience of consciousness is a property of brain activity—a phenomenon of the brain’s operation, a result of what its integrated structure creates. Subjective experience and self-awareness occur because of the integration of complex electro-chemical interactions. Just how neural processing can create the vibrancy of our subjective experience may not be a question amenable to an entirely satisfying answer; we may never possess a clear, intuitive grasp of how the feelings of vibrancy and immediacy can take place. A parallel situation exists in quantum physics, where a fully intuitive understanding has never been reached, yet physicists have the highest confidence that quantum field theory closely approximates the nature of things. Without question its operational success is unrivaled. In the case of neuroscience, confidence is high that current models of consciousness, combined with an evolutionary perspective, are progressing toward a similar status. At some point in any explanatory process an end must be reached, and without the certainty of a satisfyingly intuitive understanding. The brute fact of a phenomenon’s existence must become a given, with increasingly detailed operational descriptions developed, enhancing what we know, yet limited. In the case of neuroscience and the “hard problem” of consciousness (reaching a truly intuitive understanding of consciousness) the “problem” should become peripheral and eventually morph into a non-issue.

Viewing consciousness as a phenomenon, rather than a module or independent function of the brain, can unfetter philosophical discussion, but doing so does not force us to the opposite extreme, where either subjective experience or consciousness are deemed illusory. Quite the contrary. While the prominent philosopher Daniel Dennett is a proponent of a form of illusionist theory of consciousness, his view is highly nuanced, and never suggests subjective experience is fully an illusion. Few philosophers or neuro-scientists would dismiss the authenticity of each person’s unique, subjective experience. Our brain and perceptual systems individually interpret information received from complex environmental sources, although those perceptual interpretations of the world must not be considered a “mirror of reality”. All we can experience are finite, incomplete perspectives. In Dennett’s fuller writing about consciousness, overly simplistic views are labeled as illusions, primarily Cartesian-like models picturing the self, or consciousness, as an independent module residing within the brain, perceiving and controlling one’s ongoing actions. His largely justifiable use of “illusion” in these cases has at times been misconstrued, and led to misunderstanding his overall themes. Numerous defensible conceptions of consciousness and human agency have been proposed by others as well, consistent with current neuroscience and escaping problems of Cartesian modeling.

As mentioned earlier in the essay, Naturalism can accommodate language ordinarily used in talking about ourselves and others—we are thinking, problem-solving, decision-making and caring beings. But while the relevance and usefulness of ordinary language are not diminished within a naturalistic world view, what is conceptually imbedded in that use carries implications, and can be at odds with any number of traditional philosophical perspectives. As a likely paradigm, Naturalism’s interpretation of the phenomenon of decision-making could contain the following elements: a person’s brain is imbedded with an intricate mass of pre-existing information, an overall complexity challenging to imagine. Included are conceptual skills and patterns, memories, emotional patterns, desires, personal heuristics, biases etc.—all encoded in the complex, adaptive system called the brain. As a self-contained organism, we constantly receive environmental stimuli, with all its variability and nuance. At the moment a person consciously recognizes when a decision is needed, the brain has been receiving stimuli from the setting and concurrently processing its information base. We use the words “thinking” and “deciding” to describe the total neural activity taking place. And importantly, each of us is aware of only part of what takes place in the process of decision making. But the totality of that neural processing is what we are—it is you and I, and defines each of us as unique individuals. A person ‘s individuality emerges from the complex background of their genetic and accumulated neural information, the latter formed over a lifetime; one’s self-awareness and consciousness are but one aspect of the whole. Accepting this view does not imply humans are mere automatons, but it does offer a concept of humans as fully integrated, complex animals, and should be understood as such. And as complex animals, one’s consciousness and self-awareness do not arise from an autonomous entity found inside a physical body, but as a phenomenon created by an integrated, adaptive, biological system—a person in the holistic sense composed of atoms, molecules and electro-chemical processes. Given this naturalistic assumption, what makes it plausible to deny humans are simple automatons? The absence of specific, rigid programming in our species offers insight; the plasticity and adaptability of the human brain have given us the power of creativity, innovation and degrees of unpredictability. The species will soon learn how much of this ability might be be realized in enhanced digital systems, using self-learning programs. But regardless, the outcome will not change the reality of human adaptability and creativity, although it could tell us intelligence can have a silicon as well as a biological basis.

How do ethics and morality fit into a naturalistic perspective? A point of departure for Naturalism is the assumption of human contingency and finitude—our nature as individual biological systems. Each person’s life is brief, although unique, but our final scenarios are identical. When we die our vital systems have shut down: our heart no longer beats, breathing has ceased and electrical impulses in our brain have stopped. Our unique and precious memories have vanished. But the species continues. Accepting this shared nature is a first step toward valuing the species’ flourishing, enhancement and sustainability as the paramount human ethic. As our shared humanity is fully embraced—our essential commonality—compassion for others is more freely given. Because compassion is not being justified by the authority of sacred documents, but from understanding our place in the natural world, human empathy and caring are authentic. Authentic compassion supports an ethic where the unavoidable tension between individual desires, and the requirements of open, viable societies, can reach a suitable balance. While individuals contribute uniquely through creative thought and action, social parameters—moral norms—are equally necessary for societies to flourish, including their environmental and economic sustainability. Authentic compassion implies valuing the long-term viability of the species—the viability of human society—as a greater need than any one individual’s desires, and most adamantly whenever someone’s desires have egregious consequences for others. This stance rationalizes moral norms and legal restrictions on behavior, further reinforcing an ethic of collaborative and shared actions.

Unlike ethical perspectives where theism us used to support the presumed truth and objectivity of morality, Naturalism views moral norms as practical-based human enterprises, essential for functioning societies, and to a significant degree reflecting neural patterns in the brain. Powerful feelings of empathy and care are genuine aspects of our evolved biology, traits also found in other animals. If Naturalism’s ethical stance initially appears to lack the emotional force of traditional theism—especially its claims of intuitive certainty and after-life grace—a persuasive counter-point exists. What is needed is outright candor in assessing which world-views carry high credibility, and which do not. Naturalism has benefited from the consilience of contemporary science-based inquiry—neuroscience, cognitive-psychology, biology, the humanistic social sciences, chemistry, physics and science-grounded philosophy. The convergence of so many disciplines gives Naturalism a high likelihood that its principle assumptions present a good approximation to the character of the world. Not complete, not absolutely certain, but a world-view we can accept as reasonable and persuasive. Naturalism’s outcome is a re-defining of humanity. And for powerful emotions to support ethical actions, we need go no further than appreciating our globally shared genetic heritage, and above all, our participation in thousands of years of human culture. Reflecting on the most positive aspects of human actions—whether the most common ethical interactions, or unique, creative acts—reinforces a feeling of confidence that the human cultural enterprise carries the potential for excellence. Knowing we are participants in a complexity of phenomena so much greater than ourselves—millennia of the human cultural adventure—releases powerful bonding emotions.