During the middle decades of the 20th Century Existentialism rose to considerable prominence, influencing cultures on both sides of the Atlantic with its fusion of philosophy and psychology. Sartre, Camus and others passionately rejected theism as a world-view, substituting full acceptance of the contingencies of the world, with its random, uncertain and arbitrary nature. They saw no over-arching purpose or order to the cosmos infusing human existence with meaning, certainty and significance, that might negate human contingency. The brute fact of the brevity of our individual lives, and the absence of a privileged relationship for our species within the cosmos, drove their thought to a point of initial despair. Only self-deception or illusion could mask the truth that the nature of the world did not hold a unique meaning for human life. Sartre escaped despair through intense action and total expression of his personal freedom—human-centered actions alone.

Rejecting theism, and similarly framed metaphysical perspectives, has a history reaching as far as ancient Greece, so Existentialism is more accurately a re-thinking of a storied tradition, although an interesting and revealing one. Its growth during the troubled years before, during and after World War II may have heightened the intense, emotional style of the genre. Its adherents experienced deep angst as they confronted what they perceived to be true, which for many meant the absence of any form of transcendental meaning, once attached to religious belief (the idea of grace is an aspect of this concept). Much of Sartre’s writing describes moving beyond the despair of this loss, into a life of action, creating a focus and center for one’s life. Central themes became commitment and personal freedom, and given his circumstances and intellectual environment, this direction of his thought is not surprising, and remains a very informing read today. But it is worthwhile to note that Sartre did not see the science of his day as relevant for his philosophy, especially concerning questions of human meaning. Sartre’s reluctance is central for appreciating the divergence between Existentialism’s assumptions, and how questions of meaning are approached through the world-view of Naturalism[1].

David Hume’s philosophical instincts differed. Hume, the rock-solid, thoughtful Scottish empiricist writing nearly two centuries earlier, shared Sartre’s view of the contingency and uncertainly of the world, but his reaction was not angst, rather, a calm acceptance and continuation of his ordinary activities and creative thinking. Hume’s philosophical ideas were no less influential; I would claim a greater long-term influence for Hume. Although writing two centuries earlier, He would feel more at home with contemporary science and the world-view of Naturalism than Sartre, largely due to his greater ease with the apparent contradictions and complexity of the human animal.

Hume was a giant of the empirical tradition, embracing critical inquiry and the dearth of certainty in the world, as he and other natural philosophers of the age worked to acquire knowledge. Hume valued the iterative process needed for open inquiry and the advancing science of his own century, ideally each step building upon its predecessors. Looking at the early 21st Century’s science-oriented inquiry, these same indispensable principles are imbedded in every rapidly advancing area of study. And In both Hume’s time and our own, as interesting correlation exists between the open-ended, empirically grounded style of thinking used in the most productive inquiry, and a general acceptance, tolerance and curiosity toward uncertainty, unresolved questions and seeming paradox. Rather than causing anxiety or disquieting emotion, vexing questions and inconsistencies in data have resulted in responses of intense and creative curiosity. 20th Century examples are Einstein’s development of Special Relativity, and Neils Bohr’s work on early-stage Quantum Theory.

Today, a broadly conceived world-view of Naturalism exists, evolving in incremental fashion over decades. No single insight played a revolutionary role, but cumulatively a family of related theories have been synthesized into a credible and extensive picture of reality—a contemporary synthesis of knowledge. Being open to this world-view while Interpreting meaning, predisposes us to question former patterns of thinking, patterns that are at odds with Naturalism and open to unrelenting questions of veracity.

Naturalism’s interpretation of human meaning can be approached from multiple perspectives, and one of the more succinct comes from a recent submission in Edge.org by Steven Pinker, describing the significance of 2nd Law of Thermodynamics for understanding the Universe and our place in it. In brief, the 2nd Law states that in a physical system (one not receiving outside energy) entropy never decreases. Closed systems will become less structured and organized, eventually reaching a state of monotonous equilibrium, homogeneous and without interesting structure. Entropy is then described as high. In a biological sense the 2nd Law describes why we humans must obtain food, water and oxygen to continue living. We cannot continue long as a closed system, but require frequent inputs of energy. Quoting Pinker directly:

Why the awe for the Second Law? The Second Law defines the ultimate purpose of life, mind and human striving: to deploy energy and information to fight back the tide of entropy and carve out refuges of beneficial order.

Writing as a thorough-going postmodern Naturalist, Pinker uses the 2nd Law to inform descriptions of human actions and human meaning. As the 2nd Law implies, human life is a process charged with self-expression and affirmation—a stream of activity reflecting our interests and desires, linked to continual adaptation and learning. Life must be dynamic to continue. Our lives are constantly filled with inputs to our cognitive systems. We are engaged in multiple modes of self-expression, whether in a personal sense, or more outwardly toward others within our social circles, and ideally toward the species as a whole. Human actions can be intense and complex—emotionally, intellectually, ethically, et al. And the world around us brings less complex, yet deeply satisfying experiences. Elemental joys of the natural world, shared happiness with partners, companions and others, can be the most rewarding of human experiences. As complex animals, this is what we are about—humanism in its most elemental and robust form.

Reflecting briefly on our early predecessors’ thoughts, as they puzzled over the nature of the world, acknowledges Naturalism’s unmistakable debt to some very old ideas. Natural philosophers of both early and later classical times were absorbed by a family of knotty issues, with a telling resemblance to today’s science and philosophy. Our species’ place in the cosmos, the nature of the human psyche, the meaning of human life, all were questions open to vigorous and pointed inquiry. Early Stoic philosophy was one of the more naturalistic in emphasis, using the Latin word conatus, defined as impulse or striving, to describe the seeming innate tendency of things to exist and enhance themselves. More than a millennium later, during the early European Enlightenment, Baruch Spinoza elaborated a naturalistic interpretation of conatus where humans and nature were unified under a consistent set of laws, a pantheism where nature and God were one. Conatus became desire, a striving toward that which gives joy and avoids pain. The power of Spinoza’s thinking was his emphasis on a common conceptual scheme uniting humanity and the remainder of the natural world. In the 19th Century and into the early 20th Century, first Schopenhauer, Bergson and later Freud were influenced by the Spinozan tradition.

Contemporary Naturalism’s theories have emerged from a mass of empirical evidence, analysis, digital modeling and creative thinking, overwhelming in scale the analytical tools of earlier centuries, although we are no more intelligent or innovative in applying those tools. Current biology uses chemistry and the brain sciences to depict what the Stoics were puzzling over; the biological theory of autopoiesis describes the self-maintaining chemistry of living cells, systems capable of reproducing and maintaining themselves. And similarly, the concept of emergence gives biology and systems theory the ability to characterize the spontaneous formation of complex systems from multiple, simpler structures, including the complex human animal. The use of progressively more convergent sciences, in addition to science-based philosophical thinking, have led to a naturalistic world-view of great appeal, with definite and circumscribed implications for how the very idea of human meaning is interpreted.

Naturalism implies the phrase human meaning can make sense only by singular reference to the flow of a person’s interests, desires and modes of self-expression—our capacity to create, to care, to experience beauty and love, all that makes us human, even sadness and tragedy. Whatever satisfaction, fulfillment or happiness we experience are meaningful, and make us fortunate. By using the phrase human meaning to refer exclusively to our nature as complex biological systems, the word meaning functions much as it does in our daily speech and writing. In traditional theistic and metaphysical world-views, human meaning carries a unique and specialized use by referencing a transcendental realm—an assumption of purpose or order to the cosmos, infusing the species with meaning and significance. Humans are pictured as fully exceptional, a category of exclusion from all other animals. This use of meaning places a heavy burden of justification on its proponents—it is inconsistent with all that is known about the cosmos and the species. Naturalism implies the absence of a referent external to what we create as individuals or as members of society—an explicitly humanistic point of view.

The idea of a transcendental meaning for humanity bears close resemblance to the Aristotelian metaphysics of Final Cause, the purpose, the reason for something’s existence. Final Cause was a product of Aristotle’s brilliant and integrative mind, as he formed a conceptual structure for describing the natural world, a supreme accomplishment early in our species’ cultural development. And the idea makes sense when we talk about the intended purpose for tools and technology we create—why something is designed, its function in the broad scale of human activity. But for contemporary Naturalism, the very idea of a Final Cause is out of place whenever we examine our species’ place in the cosmos, whether we confront the ambiguous phrase human meaning, or more broadly, the meaning of human existence. For the idea of Final Cause to regain relevancy in thinking about the cosmos, a radical transformation of science and cumulative knowledge would be required. This is not logically impossible, but very unlikely.

The comprehensive nature of contemporary science-based inquiry, best described by the word “consilience”, popularized by E.O. Wilson but having an ancient origin, captures the explanatory power of synthesizing evidence from different fields of inquiry. The clearest example may be the Theory of Evolution, supported by evidence from genetics, molecular biology, paleontology, comparative anatomy and others. The background of information drawn from diverse fields creates a forceful consensus. But even the Theory of Evolution, supported by over 150 years of study and revision, cannot be claimed as absolute knowledge, but an impressive and brilliant approximation, always open to modification. The lack of absolute certainty in our knowledge—although some may wish for it—is a limitation and ambiguity to which we humans need to adapt. Accepting this lack of certainty is knowledge of a different form. The turn toward a transcendental perspective is a search for certainty, but a choice that need not be taken.

Although Sartre was not able to incorporate a relevant science-based background into his philosophy, he fully lived both the force of uncertainty and the absence of absolute truth. Contemporary Naturalism presents a comprehensive and nuanced conceptual framework, that in the 1940s, had only entered its initial stages. The work of recent decades has led to ever more inclusive descriptions of the cosmos, especially the nature of the human animal. A long-standing consensus views humans as intricate biological entities, located along a common continuum of living systems, from very simple to highly integrated and complex. We happen to be self-aware, conscious organisms, with ever-present knowledge that we inhabit a finite and very short time-span. Our lives terminate as vital systems shut down and electrical impulses in the brain stop. Sartre fully accepted this brute act, just as would many of us. But acceptance need not entail absurdity, a word frequently used in Existential literature. Rather, life’s brevity is an ordinary fact—the finite nature of all biological systems. I can see Hume acknowledging this conclusion in a matter-of-fact, accepting manner.

Naturalism views humans are extraordinarily complicated systems with conscious and pervasive non-conscious aspects, fully circumscribed by the character of the natural world. Human meaning becomes grounded in all we do as individuals living in a society. We are conscious systems acting in the world, experiencing a lifetime of actions, feelings and thoughts. And Homo sapiens’ self-reflective ability means each of us perceives life as an unpredictable and changing process. If fortunate, our actions may lead to joy, satisfaction and the pleasure of self-expression, but grief and pain are unavoidable. Emotional trauma is intrinsic to human life, no matter how privileged we might be. As a powerful and therapeutic ethic, individuals and groups are able to lessen tragedy and negative human experience. By its very existence this human tendency—our nature as empathic animals—affirms the grounding of one aspect of meaning—a culture’s shared ethical foundations. The meaning of human existence morphs into seeing human meaning as an unpretentious phrase, properly used to describe the matrix of actions and thoughts developing from a person’s interests and desires. The propensity for action, self-expression and seeking happiness—the dynamism of life—emerge from our biology in the most general sense. The electro-chemical processes of the brain make us who we are—the genesis of the interests, desires and values we own. Self-expression, in all its facets, brings human meaning—no more, no less, giving whatever satisfaction we experience. Our genetic heritage and social learning allow humans to love, nurture, create, problem-solve, feel the pleasure of physical movement—every conceivable form of experience.

How does Naturalism resolve this view of meaning when the end of one’s life nears, when everything each of us has ever experienced is about to vanish? Accepting our finite character—a beginning and an end—is accepting the cycle of all systems. Under favorable circumstances, the end of life can become a time of utter relaxation, not angst. Under more trying conditions, acceptance and fatigue may be our reality. The idea of full acceptance, not fear, ought to become a goal of our culture, a mind-set appropriate for our placement along the species’ cultural history. Accepting the nature of things reflects intellectual candor. That individuals desire a different cosmos becomes so unconvincing an argument for making the metaphysical turn. By any standard of epistemic value, Naturalism’s description of the human animal is very likely a close approximation to the nature of things—a story we can accept.

[1] Naturalism: the world described by science-based inquiry, refined through consecutive iterations, exhausts accessible reality. Knowledge is progressive, but open-ended, never complete or final. There are not two differing planes of possible experience, the natural and the supernatural, each accessible by two contrasting kinds of knowing, where one uses problem-solving, intuition and observation, and the other arises from revelation and faith. What distinguishes biological systems (including humans) is their remarkable complexity, and nothing more. The cosmos is a continuum from micro to macro, from simplicity to complexity.