Decoding the Origin of Life: Complexity, Thermodynamics, and Memory

In our latest podcast episode, Terrence Deacon & Michael Levin: What is Life? Complexity, Cognition & the Origin of Purpose, we delved into the profound question of the origin of life, engaging with the groundbreaking ideas of Terrence Deacon and Michael Levin. This blog post serves as an extended exploration of Deacon’s unique perspective, specifically focusing on the crucial roles of complexity, thermodynamics, and memory in shaping biological systems. We'll break down these complex concepts into understandable insights, offering a deeper dive into the theoretical framework that informs Deacon's views on life's emergence.

Introduction: Unveiling the Origin of Life with Deacon and Levin

The quest to understand the origin of life is one of the most fundamental and challenging endeavors in science. It requires us to bridge the gap between the non-living and the living, to explain how inert matter could have given rise to the intricate and self-sustaining systems we observe in all living organisms. While various theories exist, ranging from the primordial soup to the RNA world hypothesis, our discussion with Terrence Deacon offered a particularly insightful perspective, one deeply rooted in the principles of complexity, thermodynamics, and memory. Together with Michael Levin's unique approach to biology, the episode offered a rich tapestry of ideas about how to approach the question of the origin of life and the nature of living systems. This post aims to unpack some of the key concepts discussed, particularly those related to Deacon's framework.

The Giants of Biology: Terrence Deacon and Michael Levin

Before diving into the specifics of Deacon's arguments, it's essential to acknowledge the significant contributions of both Terrence Deacon and Michael Levin to their respective fields. Deacon, a professor of Anthropology and Neuroscience at UC Berkeley, has long been at the forefront of exploring the emergence of complexity and meaning in biological and cultural systems. His work challenges traditional reductionist approaches, emphasizing the importance of hierarchical organization and emergent properties. Michael Levin, a professor of Biology at Tufts University, is renowned for his work on morphogenesis, regeneration, and synthetic bioengineering. His research explores how cells communicate and coordinate to build and repair complex structures, often pushing the boundaries of what we thought was possible in biological systems.

Deacon's Perspective: Complexity, Thermodynamics, and Memory

Deacon’s approach to understanding the origin of life hinges on three interconnected concepts: complexity, thermodynamics, and memory. He argues that these three elements are not merely features of living systems, but are fundamental to their very existence. According to Deacon, life is not just a complex chemical reaction, but a unique form of organization that harnesses thermodynamic principles to create and maintain a historical record – a form of memory – that shapes its future behavior.

Complexity as a Foundation for Life

Complexity, in Deacon's view, is more than just intricacy; it's about hierarchical organization and the emergence of novel properties at different levels of organization. Living systems are characterized by a nested hierarchy of structures, from molecules to cells to tissues to organs, each level exhibiting properties that cannot be simply predicted from the properties of its constituent parts. This emergent complexity is crucial for life's ability to adapt, evolve, and maintain itself in the face of environmental challenges. A key aspect of Deacon's concept of complexity is the idea of constraints. He argues that complexity arises not simply from adding more components, but from imposing constraints on those components, thereby channeling their interactions and giving rise to new functionalities. These constraints, he suggests, are essential for the emergence of self-organizing systems that can maintain themselves far from equilibrium.

Thermodynamics: Energy's Role in Life's Processes

Thermodynamics, the study of energy and its transformations, plays a central role in Deacon's understanding of life. Living systems are inherently thermodynamic systems, constantly exchanging energy with their environment. However, life is not simply about dissipating energy; it's about harnessing energy to create and maintain order. Deacon emphasizes the importance of "dissipative structures," systems that maintain their organization by dissipating energy into their surroundings. These structures, such as convection cells or hurricanes, are self-organizing and self-maintaining, but they also require a constant input of energy to persist. Life, according to Deacon, is a particularly sophisticated type of dissipative structure, one that is capable of self-replication, adaptation, and evolution. Furthermore, Deacon highlights the importance of "autocatalysis" in the origin of life. Autocatalytic sets are collections of molecules that catalyze each other's formation, creating a self-sustaining cycle of chemical reactions. Such cycles can create local pockets of order and complexity, paving the way for the emergence of more complex biological systems. He posits that life emerged as a unique type of autocatalytic system that is also capable of creating and maintaining its own internal constraints.

Memory: Shaping Biological Systems Through Time

Memory, in Deacon's framework, is not just a cognitive faculty, but a fundamental property of living systems. He argues that life is inherently historical, shaped by its past experiences and encoded in its structure and function. This memory is not necessarily stored in DNA alone, but also in the organization of cells, tissues, and even entire organisms. One of the key ways that life embodies memory is through the process of development. The development of an organism from a single cell to a complex adult form is a historical process, guided by a developmental program that is encoded in the organism's genome and epigenetic modifications. This developmental program acts as a form of memory, shaping the organism's structure and function according to its evolutionary history. Furthermore, Deacon emphasizes the role of learning and adaptation in shaping biological systems through time. Organisms are constantly learning from their environment, adapting their behavior and physiology to better cope with the challenges they face. This learning process creates a form of experiential memory, which can be passed on to future generations through cultural transmission or epigenetic inheritance. According to Deacon, this capacity for memory is what allows life to evolve and adapt to changing environments, and it is a key feature that distinguishes living systems from non-living matter.

Contrasting Views: Deacon vs. Levin

While both Deacon and Levin are interested in the origin of life and the nature of biological systems, they approach these questions from different perspectives. Deacon tends to focus on the thermodynamic and semiotic aspects of life, emphasizing the role of constraints and meaning in shaping biological processes. Levin, on the other hand, is more focused on the computational and regenerative capabilities of living systems, exploring how cells communicate and coordinate to build and repair complex structures. This contrast in perspectives leads to some interesting disagreements, particularly regarding the role of genes and the nature of teleology in biology. Deacon is critical of what he sees as a gene-centric view of life, arguing that genes are not the sole determinants of biological form and function. He emphasizes the importance of epigenetic factors, environmental influences, and self-organizing processes in shaping biological systems. Levin, while acknowledging the importance of these other factors, still believes that genes play a crucial role in encoding the basic blueprints for life. Similarly, Deacon and Levin have different views on the nature of teleology in biology. Deacon argues that living systems are inherently teleological, meaning that they are oriented towards specific goals or purposes. He believes that this teleology arises from the constraints and self-organizing processes that characterize life. Levin, while not necessarily disagreeing with this view, is more cautious about attributing goals or purposes to biological systems. He prefers to focus on the underlying mechanisms that give rise to the appearance of teleology, rather than assuming that teleology is a fundamental property of life.

The Self, Beneficiaries & Causal Emergence

One of the more philosophical aspects of the discussion between Deacon and Levin revolves around the concept of the "self" in biological systems. Deacon argues that living systems are characterized by a sense of self, a boundary that separates them from their environment and allows them to maintain their identity over time. This sense of self is not necessarily conscious, but it is essential for life's ability to self-organize and self-maintain. Furthermore, Deacon emphasizes the importance of beneficiaries in understanding the origin of life. He argues that life is inherently oriented towards benefiting itself, towards increasing its own survival and reproduction. This self-benefiting behavior is not necessarily intentional or conscious, but it is a fundamental property of living systems. The concept of causal emergence is also central to Deacon's view of life. He argues that life is characterized by the emergence of new causal powers at higher levels of organization. These causal powers cannot be simply reduced to the properties of the constituent parts, but arise from the interactions between those parts and the constraints that are imposed on them. For example, the ability of a cell to divide and reproduce is a causal power that emerges from the complex interactions between its various molecules and organelles. This causal emergence is what allows life to evolve and adapt to changing environments.

Strange Loops & Semiotics

Deacon introduces the idea of "strange loops" to describe the self-referential nature of living systems. A strange loop is a hierarchical structure in which higher levels of organization influence and are influenced by lower levels, creating a circular pattern of causality. This circularity is what allows living systems to be self-organizing and self-maintaining. Deacon also emphasizes the importance of semiotics, the study of signs and symbols, in understanding life. He argues that living systems are inherently semiotic, meaning that they are capable of interpreting and responding to signs in their environment. This semiotic capacity is what allows life to learn, adapt, and evolve. According to Deacon, the metabolism of an organism precedes its neural activity. This means that the basic processes of energy acquisition and utilization are fundamental to life, and that cognition and consciousness are emergent properties that arise from these basic processes. This view challenges the traditional notion that neural activity is the primary driver of behavior, suggesting instead that the body's metabolic state plays a crucial role in shaping cognition and consciousness.

Regeneration & Memory

The discussion between Deacon and Levin also touches on the topic of regeneration, the ability of living systems to repair and replace damaged tissues and organs. Levin's research has shown that some animals, such as planarians, have remarkable regenerative capabilities, capable of regrowing entire bodies from small fragments. This regenerative capacity is a testament to the power of self-organizing processes in biological systems. Deacon argues that regeneration is closely linked to memory. He believes that the ability to regenerate requires a form of memory, a record of the organism's past structure and function that guides the regeneration process. This memory is not necessarily stored in DNA alone, but also in the organization of cells and tissues. Deacon also uses the term "decompression processes" to describe the way that living systems unfold and develop over time. He argues that the genome can be seen as a compressed representation of the organism's developmental program, which is decompressed and unfolded during development. This decompression process is guided by epigenetic factors, environmental influences, and self-organizing processes.

Constraints & Meta-Constraints

As previously mentioned, constraints are central to Deacon's view of life. He argues that complexity arises not simply from adding more components, but from imposing constraints on those components, thereby channeling their interactions and giving rise to new functionalities. These constraints are essential for the emergence of self-organizing systems that can maintain themselves far from equilibrium. Furthermore, Deacon introduces the concept of "meta-constraints," constraints on constraints. Meta-constraints are higher-level organizing principles that shape the way that constraints interact with each other. These meta-constraints are essential for the emergence of complex and adaptive systems. The concept of meta-constraints is particularly relevant to understanding problem-solving agents. Deacon argues that problem-solving agents are characterized by their ability to impose constraints on their own behavior, thereby narrowing down the range of possible actions and increasing their chances of success. These constraints are not fixed or predetermined, but are constantly being modified and adapted in response to the agent's environment.

Conclusion: A New Understanding of Life's Origins

Terrence Deacon's perspective on the origin of life, as explored in our podcast episode Terrence Deacon & Michael Levin: What is Life? Complexity, Cognition & the Origin of Purpose, offers a compelling alternative to traditional reductionist approaches. By emphasizing the roles of complexity, thermodynamics, and memory, Deacon provides a framework for understanding how life could have emerged from non-living matter and how it continues to evolve and adapt. His insights challenge us to rethink our assumptions about the nature of life and to explore new avenues of research in biology, cognitive science, and philosophy. By considering life as a unique form of organization that harnesses thermodynamic principles to create and maintain a historical record, we can gain a deeper appreciation for the intricate and dynamic nature of living systems. Furthermore, by acknowledging the importance of constraints, self-organizing processes, and semiotic interactions, we can develop a more holistic and integrated understanding of the origin and evolution of life.