What does it mean to be biologically autonomous?

This article examines biological autonomy in the life sciences, focusing on how functional integration links constitution, interaction, and teleology in living systems.

Introduction

What exactly is autonomy? On the one hand, the term intuitively suggests an independence of biological systems from their surroundings. On the other hand, living beings are not isolated from their environment and constantly interact with it. This dialectic is clearly exemplified by the process of feeding: organisms undertake metabolic activities that are not causally determined by the environment; yet, metabolism necessitates that organisms interact with their environment to obtain nutrients.

Philosophers have proposed various, not mutually exclusive, meanings of biological autonomy: the ability of human beings to perform intentional acts (e.g., Collier 1999; Enç 2003; Lumer and Nannini 2016; Gallagher 2023); the capacity of an organism to self-maintain, act, and transform its environment (e.g., Bickhard 2000; Moreno and Etxeberria 2005; Moreno and Mossio 2015); and the foundation of the goal-directed nature of living beings, also known as teleology (Mossio, Saborido, and Moreno 2009; Moreno and Mossio 2015; Mossio and Bich 2017).

All these interpretations of biological autonomy necessitate the formulation of a concept of functional integration. For instance, intentionality can arise if certain areas of the brain are functionally connected and physiologically integrated. Similarly, an organism’s self-maintenance and action are properties of the entire system that emerge due to the functional integration among its component parts.

Living beings as autopoietic systems

Biologists Humberto Maturana and Francisco Varela introduced the concept of autopoiesis in the 1970s to describe systems capable of producing and maintaining their own organisation. An autopoietic system has two key characteristics: it is generated by a network of interconnected components, and the mutual dependence of these components creates a cohesive material unit with clear spatial boundaries.

The cell is a paradigmatic example. It consists of a network of biochemical reactions whose interactions continuously generate and sustain the network itself. In such systems, the organisation of the whole remains stable even though the individual components are constantly replaced or transformed.

Autopoiesis also helps distinguish living systems from artificial systems such as machines. Both machines and living organisms are composed of organised parts that produce specific behaviours. However, in machines the properties and functions of the parts are determined by an external designer, and their use depends on the broader social context in which they operate.

Living systems differ because their organisation arises from the internal relations among their components. They continuously renew their parts while maintaining their organisation. In this sense, living beings are autonomous systems whose functional integration allows them to sustain and reproduce themselves.

Constitutive autonomy

Maturana and Varela largely equate biological autonomy with autopoiesis: a system is autonomous because it can regulate the flow of energy and matter to sustain its own organisation. However, this view does not fully clarify how living systems relate to their environment, which has led to debates about the nature of biological autonomy. One way to address this issue is to distinguish two complementary forms of autonomy.

The first is constitutive autonomy, which refers to the internal processes that allow an organism to maintain itself. A central component is metabolism, through which organisms transform nutrients into energy and molecular building blocks. Metabolic reactions are organised into enzyme-driven pathways that rely on enzymes and energy intermediates to sustain cellular activity.

Another key dimension is gene expression, the process by which genetic information in DNA is used to produce functional molecules such as RNA and proteins. These molecules enable essential cellular processes and allow cells to renew their components. A third dimension is biological regulation, which includes biochemical mechanisms that coordinate metabolic and genetic activities.

Together, these processes illustrate functional integration: each forms an interdependent network (e.g. metabolism relies on interconnected biochemical pathways), and metabolism, gene expression, and regulation mutually support one another to sustain the autonomy of living systems.

Interactive autonomy

The second dimension of biological autonomy is interactive autonomy, which refers to the capacity of living beings to interact with and transform their environment through their actions. While constitutive autonomy concerns the internal processes that sustain an organism, interactive autonomy focuses on how the organism engages with the world. These actions vary widely across organisms: bacteria may secrete molecules or move toward chemical signals, whereas humans perform intentional actions such as voluntary movements or speech.

Interactive autonomy is closely related to the philosophical concept of agency, understood as the capacity of a system to act. However, defining agency too broadly raises difficulties. Artificial systems such as robots or nanomachines can also act on their environment, which may blur the distinction between biological and artificial agents. Moreover, agency takes different forms across life (from bacteria to humans) making the concept potentially ambiguous.

Despite this diversity, interactive autonomy shares several basic features across organisms. It involves sensorimotor coupling (the coordination of sensing and acting), depends on the internal processes of constitutive autonomy (metabolism, gene expression, and regulation), enables adaptive behaviour, and characterizes the organism as a whole rather than its individual parts.

Where does functional integration appear in this picture? In fact, it plays two crucial roles. First, interactive autonomy depends on the integration of internal processes: organisms can interact with their environment only because their constitutive capacities (metabolism, gene expression, and regulation) work together. Second, interaction itself requires the integration of different functions, such as the coordination between sensory and motor capacities.

Autonomy and teleology

The philosopher Immanuel Kant was among the first to highlight a close connection between teleology, autonomy, and the organisation of living beings. In the Critique of Judgment (1790), particularly in the First Introduction (§6), Kant distinguishes two ways of describing natural systems: mechanistically and teleologically. A mechanistic description explains natural phenomena by analysing the interactions of their component parts. A teleological description, by contrast, considers a system as a whole whose parts are organised in relation to certain ends or purposes. For example, the behaviour of plants and animals can be studied by examining the mechanisms of their organs and tissues, but it can also be understood by considering how these parts contribute to the functioning and persistence of the organism as a whole.

Building on Kant’s insight, we can see that constitutive and interactive autonomy are closely connected to teleology. The internal processes that make up constitutive autonomy (metabolism, gene expression, and regulation) are organised in ways that sustain the organism. In other words, they contribute to the organism’s self-maintenance. This self-maintenance establishes the norms that guide an organism’s functioning: living beings must keep many physiological variables (such as body temperature, heart rate, or blood pressure) within certain ranges in order to survive.

Interactive autonomy also has a teleological dimension. When organisms act on their environment, their actions are typically directed toward goals that support their continued existence. Seeking nutrients, avoiding harmful conditions, or maintaining suitable environmental conditions are all examples of actions that contribute to the organism’s persistence. In this sense, the autonomy of living beings is inseparable from a form of goal-directed organization.

Conclusion

Autonomy is a key feature of living beings, but it does not simply mean independence from the environment. In fact, the opposite is true. To be autonomous is to depend on the environment for the resources necessary to sustain oneself—this is what we called constitutive autonomy. At the same time, autonomy also involves the capacity to actively interact with the environment and shape it according to the organism’s own norms. This is interactive autonomy.

Together, constitutive and interactive autonomy help explain in what sense organisms display an internal teleology. The processes that sustain life are organised in ways that contribute to the persistence of the organism itself. This internal teleology also marks an important boundary between natural biological systems (such as bacteria, plants, or animals) and artificial biological systems, such as biorobots or organs-on-chips. In principle, artificial systems can be designed to self-maintain and interact with their environment. However, their organisation and functioning ultimately depend on an external agent, such as a human engineer. Moreover, the adaptive behaviour and plasticity that characterise living organisms remain extremely difficult to reproduce artificially.

At the heart of these processes lies functional integration. Biological mechanisms are organised in ways that support both constitutive and interactive autonomy, as well as the close interdependence between them. This integration helps explain how organisms maintain their internal coherence while continuously interacting with their surroundings.

The integration of constitutive and interactive autonomy also provides a useful framework for understanding biological individuality. A system can be considered a physiological individual if it is capable of maintaining itself and interacting effectively with its environment. If, in addition, it possesses reproductive capacities and can transmit variations to its offspring, it can also be regarded as an evolutionary individual.

For more details see Chapter 2 of the Book Functional Integration: A Theoretical Enquiry into the Biological Unit of the Individual.

This article is part of a series on functional integration and biological individuality.