What Is Life?

Life as an Emergent Dynamical Property of Causally Organized Matter

Life is made of matter. But life is not simply another name for that matter. A living organism is a materially embodied system whose components stand in organized causal relations and whose active dynamics realize a system-level living state. This distinction matters because the material components of an organism can remain while the organism-level property we call life has already been lost. Connection Theory therefore begins with a different question:

What causal organization must matter possess and realize for a living state to exist, and what organization must remain available for that living trajectory to continue across change?

1. The Parts Can Remain When the Life Is Gone

Consider a human body shortly after death. Its DNA has not disappeared. Most proteins, membranes, cells, organs, and visible anatomical structures remain. Death does not instantaneously destroy every component or stop every local chemical process.

Post-mortem tissues can retain molecular activity (Pozhitkov et al., 2017), and whole-body OrganEx experiments in pigs have shown that selected molecular and cellular processes can be restored after one hour of warm ischaemia (Andrijevic et al., 2022). But restoring local biological activity is not the same as restoring the organism as one living individual. This gives the opening clue:

Life is neither an isolated property of one component nor the arithmetic sum of local biological activities.

The parts matter. But the living property belongs to what those parts do together as an organized system.

2. What Makes an Aircraft Fly?

An aircraft contains wings, engines, control surfaces, sensors, a fuselage, and supporting structures. Each component has local capacities. A wing can redirect airflow. An engine can generate thrust. A sensor can detect a variable. But no component possesses flight by itself. Even a fully assembled aircraft sitting on a runway is not currently flying. The structure preserves the capacity for flight. Flight itself appears only when the aircraft enters an appropriate dynamical relation with its environment.

Lift, drag, thrust, weight, orientation, airflow, sensing, and control must form a viable operating regime through time. If that regime breaks down, flight can disappear while most of the aircraft remains intact. This illustrates a general structure: Components → Causal Organization → Active Organized Dynamics → Emergent System-Level Property Flight is not an extra substance hidden inside the aircraft.

It is a property realized when the organized system operates in the relevant dynamical regime. Life, I propose, should be approached in the same general way.

3. Components, Causal Organization, and Dynamics

These levels should be separated carefully.

Components

Components possess local capacities. Cells metabolize. Membranes regulate transport. Enzymes catalyse reactions. Neural tissue propagates signals.

Causal interaction

Components affect one another. Signals alter downstream states. Transport changes concentrations. Mechanical forces change structure.

Causal organization

Some interactions become regularized into persistent relations through which the system repeatedly operates. These relations organize:

• transport;
• signalling;
• regulation;
• metabolism;
• repair;
• resource allocation;
• coordination.

Organization is therefore not merely spatial arrangement. It is a structured pattern of causal relations that differentiates the system's internal organization from its broader environment.

Active dynamics

Flows, feedbacks, timing relations, state transitions, and coordinated processes actually run through that organization.

Emergent property

When the causal organization is actively realized in the appropriate dynamical regime, system-level properties can appear. A static anatomical diagram can show components and nominal relations. It cannot by itself tell us whether the organism is currently realizing the dynamics required for life.

4. Structure Is Necessary but Not Sufficient

A recently dead organism demonstrates this sharply. Much of the structure remains. But the active causal organization that previously coordinated circulation, metabolism, signalling, repair, and regulation no longer functions as one integrated living system. This is why:

Preserved structure is not equivalent to preserved living dynamics.

The same broad structural substrate can support very different dynamical regimes. A heart can beat normally, fibrillate, or stop. Neural tissue can support coordinated activity, seizure-like synchronization, or silence. The material is important. But what the system is doing depends on the operating causal relations.

5. Life Is Not Simply Dissipation

Living systems are open systems. They exchange matter and energy with their environments and maintain organized states far from thermodynamic equilibrium. This connects life to the broader physics of dissipative structures. Flames, whirlpools, and storms also persist through ongoing throughput. Their constituent matter changes while a larger pattern remains. But not every dissipative structure is alive. A flame can:

• consume fuel;
• maintain a recognizable form;
• spread under suitable conditions.

A storm can:

• persist;
• move;
• reorganize large-scale flows.

These are genuine emergent dynamical systems. But they do not ordinarily exhibit the same kind of internally organized contribution to repair, replacement, regulation, and continued self-maintaining organization found in living systems; nor do they normally participate in lineages with structured causal heredity and heritable variation. So:

Dissipation can sustain organization, but dissipation alone does not define life.

6. What Is Special About Living Dynamics?

The crucial difference is not that living systems are dynamic while nonliving systems are static. Many nonliving systems are highly dynamic. The difference is that living dynamics participate in maintaining and renewing the causal organization through which life continues. A living cell does not merely permit chemical reactions to occur. Its ongoing organization contributes to:

• regulating exchange;
• maintaining gradients;
• allocating resources;
• repairing damage;
• replacing components;
• coordinating internal processes;
• altering behavior when conditions change.

This can be summarized as a causal loop: Causal Organization → Living Dynamics → Maintenance / Repair / Reorganization → Continued Causal Organization. Life is therefore not only dynamically realized. Its dynamics contribute to preserving the organization that allows those dynamics to continue.

This preservation is not material stasis. Living organization continuously reconstructs itself while matter and cells turn over. It also regulates the boundary conditions under which matter, energy, signals, and other causal influences enter and leave. In this sense, living persistence depends on controlled openness plus continuous organizational reconstruction, not on permanent components.

7. Regulation and Adaptation Are Not the Same

Living systems contain extensive regulation. Temperature control, ion regulation, metabolic control, and many other processes can operate through established response structures. But regulation should not automatically be equated with adaptation. A regulatory process executes an existing organization of responses. Adaptation involves consequence-sensitive change in the system itself that alters its subsequent relation to the actual environment. A living system can therefore contain both: regulatory dynamics and adaptive change The distinction matters because fixed control alone is not enough to explain the broader flexibility of living organization. Life requires regulatory stability, but living organization can also change through development, learning, physiological adjustment, remodeling, and other historically accumulated processes.

8. Living Systems Are Not Fully Autonomous

It is tempting to define life by saying that a living system maintains itself. But no known organism is causally independent of its environment. Cells require nutrients. Animals require energy and appropriate physical conditions. A fetus depends on the placenta. A patient can depend on dialysis, ventilation, medication, or implanted devices. External dependence does not automatically remove life. The better question is:

What causal contribution does the organism's own organization make to maintaining its continued living state?

This contribution can be distributed. Some functions may be largely internal. Others may depend strongly on environmental or technological support. The relevant system boundary therefore needs to be stated rather than assumed.

9. Life Persists Through Causal-Organizational Change

A living organism does not remain alive by keeping its matter fixed. Water enters and leaves. Proteins are synthesized and degraded. Cells divide, differentiate, migrate, and die. Tissues remodel. Development transforms the organism. Yet later states can remain part of the same continuing life. The relevant continuity is not material sameness. It is:

continuity of causal organization through transformation

During ordinary turnover, this can be analysed as Organizational Persistence: the organism remains a continuing bounded relational organization while components are replaced. Across a substantial interruption and later resumption, the stricter Organizational Continuity question asks whether the same causal lineage continues.

A later state is produced through the continuing causal history of the earlier living system—through operation, modification, repair, reorganization, or preservation across an interruption. The causal relations do not remain identical. They change. But they change within the historically continuous causal lineage of the same organization; that lineage need not imply uninterrupted activity at every moment. This is why a living organism is better understood as a trajectory than as a snapshot.

10. Low Activity Does Not Necessarily Mean Loss of Life

If life is dynamically realized, does life disappear whenever activity becomes extremely weak? Not necessarily. Some organisms can enter states in which active metabolism and observable dynamics are greatly suppressed. What matters is whether the embodied causal organization required to regenerate viable living dynamics remains materially preserved. It is useful to distinguish:

Active living dynamics

The characteristic flows, regulation, transport, metabolism, repair, and coordination are actively operating.

Strongly suppressed dynamics

Activity is greatly reduced, but some organization-preserving processes may continue.

Preserved living organization

Current activity may be extremely low, but the material causal organization needed to resume viable living dynamics remains intact.

Lost recoverability

The organization has deteriorated beyond the conditions under which the same living system can return to viable operation under the stated environmental and intervention conditions. The important distinction is therefore between:

temporary suppression of living dynamics

and

loss of the organization capable of realizing those dynamics

This will become central when discussing death.

11. Recoverability Is About the Same Organization

Recovery should not be confused with reconstruction. Suppose a dormant biological system later resumes viable activity. If the same materially embodied causal organization has been preserved through the interruption, the later dynamics can continue the earlier living trajectory. Now imagine instead that the original organization is destroyed and a new system is built from a detailed external description. The new system may be extremely similar.

It may reproduce many of the same functions. But similarity does not by itself establish continuation of the same biological individual. For life, recovery therefore concerns whether the continuing organization remains capable of returning to a viable living regime under the stated conditions. The stronger identity question—whether the resumed system is the same individual—requires a separate analysis of causal-organizational continuity.

12. Emergent Living Properties Can Appear and Disappear Gradually

Emergence does not require one mysterious instant. Some system-level capacities can develop gradually as causal relations become established. Others may appear when an operating system crosses into a new dynamical regime. Birth illustrates this. A fetus is alive before birth. But extrauterine life requires a major reorganization of respiratory and circulatory dynamics. The organs are already present. What changes is the operating causal regime. Likewise, during severe injury or dying, local processes may continue while organism-level coordination progressively deteriorates. The scientific question is not simply:

Is anything still happening?

It is:

Is the causal organization that realizes the living organism still operating, or still materially preserved in a form capable of resuming viable dynamics?

13. Life Is a System-Level Property, Not a New Substance

Calling life emergent does not imply that an additional entity appears above the components and begins controlling them. The physical causes remain the components and their interactions. The system-level description identifies a causal regularity that belongs to the organized whole. This is similar to describing:

• circulation;
• flight;
• coordinated locomotion;
• a hurricane.

Macro-level language is useful when system-level variables explain and predict behavior that is difficult to understand by listing isolated local events. Life belongs to this class of dynamically realized system-level properties.

14. A Working Definition of Life

Connection Theory proposes the following working definition:

Life is an emergent dynamical property of physically embodied causal organization. The living state is actively realized when the system's organized causal relations generate coordinated dynamics that contribute to maintaining, repairing, regulating, and reorganizing the continuing living system through interaction with its environment. Living individuals belong to lineages in which organization can be reproduced with causal heredity and heritable variation.

During strongly suppressed states, living continuity may persist when the physically embodied causal organization needed to resume viable living dynamics remains preserved under the stated environmental and intervention conditions. The lineage clause is not a requirement that every individual actually reproduce. A sterile individual, a juvenile, or an individual that never produces offspring can still be alive; the criterion concerns the reproductive organization of the lineage or kind to which the individual belongs. Living status is attributed to the individual organization; reproductive capacity, causal heredity, and heritable variation enter the discriminator at the lineage level. Several parts of this definition matter.

Physically embodied

Life is not an immaterial substance. The physical substrate can matter enormously without being restricted in advance to one chemistry.

Causal organization

Life depends on regularized causal relations among components, not merely their inventory or spatial arrangement.

Dynamical

Life is actively realized through operating flows, feedbacks, timing relations, and state transitions.

Emergent

The living property belongs to the organized system and is not reducible to an isolated component.

Continuing living system

Living states are historically connected through transformation of the causal organization.

Lineage reproduction and heredity

Self-maintenance is not enough by itself. A living lineage must be able to generate independently continuable descendants through a causal reproductive process in which organization is inherited and variation can itself be inherited across generations. Mere copying or externally engineered duplication does not establish this on its own.

Environmental relation

A living system is open to its environment and cannot be understood as an isolated object.

15. A Stricter Test for Artificial Life

A self-monitoring AI organization could eventually repair components, replace failed agents, regulate access, reorganize workflows, and preserve itself through disruption. Those properties would make it a highly autonomous and adaptive artificial organization. They would not, by themselves, be enough to classify it as artificial life under this working account.

For an artificial organization to enter the stronger category of a living artificial lineage, this proposal requires at least:

1. Reproduction — the organization can generate an independently continuable descendant rather than merely start another temporary worker or duplicate a mature runtime.
2. Causal heredity — the descendant inherits substantial organization, developmental rules, priors, or response-generating dispositions through a traceable parent–offspring causal path.
3. Heritable variation — descendants can differ in organizationally relevant ways, and at least some of those differences can themselves be transmitted to later generations.

For complex adaptive AI, I propose one further and stronger developmental test:

The offspring should inherit a lineage, not merely an adult state. It should regenerate the capacity to develop capability again under its own environment.

That means a descendant need not be a blank slate, just as a human infant is not. It can inherit architecture, learning rules, priors, maintenance organization, and selected knowledge. But it should not simply freeze and reproduce the parent's entire mature adaptive state. A new generation should reopen a comparatively high-plasticity developmental window in which its organization can form or revise capabilities in response to the environment it actually encounters.

This renewed adaptive plasticity is proposed here as an additional discriminator for complex adaptive artificial lineages, not as part of the minimal reproduction–heredity–variation condition and not as a universal claim that every biological species must exhibit a human-like juvenile phase. It separates two forms of continuity:

• within-lifetime adaptation — an individual changes through consequence-sensitive interaction;
• intergenerational adaptation — a lineage transmits organization with variation while regenerating descendants able to adapt to their own environment.

This distinction also prevents historical overfitting from being confused with heredity. A lineage can preserve what remains valuable from the past without forcing every descendant to begin as a mature copy optimized for an earlier environment.

Ordinary present-day companies and current AI systems do not normally satisfy these living-lineage conditions. But no organizational substrate is categorically excluded in advance: a future artificial organization would be judged by the same causal criteria rather than by whether it is called a company, an AI system, or something else.

Whether future artificial systems satisfying these causal conditions should socially, legally, or morally be recognized as living beings is a separate question for human civilization. The scientific task here is narrower: to specify the causal organization that would make such a classification physically serious rather than metaphorical.

16. What This Definition Does Not Claim

This working definition does not imply:

• that every dissipative structure is alive;
• that every regulatory system is alive;
• that complete autonomy is required;
• that every biological process must remain continuously active;
• that material components must remain unchanged;
• that similarity is sufficient for identity;
• that a system is excluded from life merely because its substrate is artificial;
• that self-maintenance or self-copying alone is sufficient for artificial life.

Nor does it settle every difficult case. Viruses, synthetic cells, obligate symbioses, deeply dormant organisms, technologically supported organisms, future biological–artificial hybrids, and artificial lineages that approach the criteria above may require more specific tests. The purpose of the definition is not to eliminate boundary cases. It is to identify what must be examined.

17. The Central Claim

The intuitive version is:

Life is not the material of the organism alone. Life is what causally organized matter does when its active dynamics help sustain and renew the organization through which the organism continues.

A compact structure is: Matter → Causal Interaction → Causal Organization → Active Organized Dynamics → Emergent Living Property with a continuing relation: Living Dynamics → Maintenance / Repair / Reorganization → Continued Causal Organization. At the lineage level: Reproduction → Causal Heredity + Heritable Variation → New Living Organization. The components are indispensable. But components alone are not life. Structure makes living dynamics possible. Active causal organization realizes them. Historical continuity carries the individual through change, while reproduction carries organized lineage across generations. And when active dynamics become strongly suppressed, physically preserved organization may retain the capacity for the same living system to resume.

Matter makes life possible.
Causal organization makes life a system.
Active dynamics make life real.

18. The Next Question

A living system cannot persist by sealing itself completely away from its environment. It must exchange matter and energy. It must preserve internal organization while allowing selected causal interaction across its boundary. This raises the next question:

If a living system must remain open to its environment, where does the organism actually end?

Part II — A Boundary Is Not a Line

References

• Andrijevic, D., Vrselja, Z., Lysyy, T., et al. (2022). Cellular recovery after prolonged warm ischaemia of the whole body. Nature, 608, 405–412. DOI: 10.1038/s41586-022-05016-1.
• Pozhitkov, A. E., Neme, R., Domazet-Lošo, T., et al. (2017). Tracing the dynamics of gene transcripts after organismal death. Open Biology, 7(1), 160267. DOI: 10.1098/rsob.160267.