In our last lesson, we established the foundational definition of cybernetics as the study of "control and communication in the animal and the machine." We saw through the examples of the steersman, the kitten, and Grey Walter's tortoises that this new science is fundamentally concerned with systems that use feedback to navigate their world and achieve goals. The common thread in all these examples was a loop: an action's result is sensed and fed back to influence the next action.
Today, we will give this fundamental structure its formal name and explore its profound implications. The learning outcome for this lesson is to define circular causality and illustrate it with examples from biological and engineered systems. We will move beyond the intuitive idea of a "feedback loop" to understand circular causality as a radical departure from traditional linear thinking, and as the very engine of all regulatory and adaptive behavior.
From Straight Lines to Closed Loops
For centuries, the dominant model of causation in Western science has been linear, like a chain of dominoes: A causes B, which then causes C, and so on. This is the "billiard ball" universe, where effects follow causes in a predictable, one-way sequence. The cyberneticians of the mid-20th century realized this model was critically incomplete for explaining the complex, self-regulating systems they were interested in.
This first video introduces this paradigm shift, contrasting the old mechanical vision with the new cybernetic one.
UNIVERSO KUBERNETES 1/3 PART ONE: THE CYBERNETIC VISION
This documentary, "Universo Kubernetes," sets the stage by contrasting the reductionist, linear "cause-and-effect" methods of classical science with the systemic view of cybernetics.
First, watch the segment from the beginning of the clip to understand the limitations of the "clockwork" or "billiard ball" view of the universe when trying to explain complexity. Then, watch the section from the definition of feedback. This part explicitly defines the feedback mechanism and introduces the core concept for today's lesson: circular causality.
As the video explains, in a circular causal system, the clear distinction between cause and effect breaks down. The output of an action circles back to become an input that modifies future action. In essence, A causes B, which in turn influences A. This seemingly simple idea was revolutionary.
A Science of Loops
The recognition of circular causality wasn't a minor tweak to existing science; it was the foundational principle of cybernetics. This idea was so central that it was embedded in the very first Macy Conference title: “Feedback Mechanisms and Circular Causal Systems in Biological and Social Systems.”
Let's explore this history and formalize the definition with an excellent article that traces the concept's origins.
Circular Causality: A Short History (with receipts) | by Maddy Muscari
This article by Maddy Muscari provides a concise history of how circular causality became the cornerstone of cybernetic thought.
Please read the first two sections of the article. Start with the introduction, which gives a direct definition and lists the key thinkers involved. Continue through the next section, "Loops Take the Wheel". Pay close attention to how Warren McCulloch applied the idea to neural networks and how Heinz von Foerster identified circularity as the "one central concept" of cybernetics.
As you've just read, what were once dismissed as logical paradoxes or "vicious circles" were now seen as "virtuous loops"—the very mechanism for intelligence, memory, and life. This shift from linear to circular thinking is one of the most important conceptual leaps in 20th-century science. A key goal of all cybernetic modeling is precisely to see causality as a loop.
Engineered Causality: The System Controls Itself
Let's ground this abstract principle in some concrete engineered examples. You'll see that the logic is the same, whether the components are mechanical, electrical, or digital.
1. The Thermostat
The thermostat is the quintessential example of a simple cybernetic device. Its goal is to maintain a set temperature. It achieves this through a circular causal loop:
- Action: The furnace turns on, heating the air.
- Sensing: The thermostat's sensor measures the air temperature.
- Comparison & Feedback: When the temperature rises to the setpoint (goal), the thermostat sends a signal (feedback) to the furnace.
- Corrective Action: The furnace turns off.
- ...The air then cools, the sensor detects this, and the loop begins again.
The effect (heated air) has circled back to influence its cause (the furnace).
2. The Buzzer Circuit
Your background in computer science will make this electrical example particularly clear. The Medium article you read earlier uses a simple buzzer to show how circular causality can even challenge the limits of classical logic.
Circular Causality: A Short History (with receipts) | by Maddy Muscari
Let's return to the article "Circular Causality: A Short History" for this example.
Find the section titled "Not Vicious, but Vital: Circular Cause as Cognition." Read Gregory Bateson's analysis of the buzzer circuit. The key insight here is that a simple linear IF...THEN statement cannot describe the system's behavior over time.
In the buzzer, the flow of current (cause) creates a magnetic field that breaks the circuit (effect), which stops the current (new cause), which collapses the field and closes the circuit (new effect), and so on. This self-interrupting cycle, where leads to , is a perfect, tangible example of circular causality in action. It's not a logical contradiction; it's a dynamic process unfolding in time.
Biological Causality: The Logic of Life
The true power of the cybernetic vision comes from realizing that this same looping logic governs the living world. The principle is substrate-independent; it doesn't matter if the medium is electrons in a wire or proteins in a cell.
1. Homeostasis
The thermostat is an engineered device that mimics a fundamental biological process: homeostasis. Your body maintains a stable internal temperature of around 37°C (98.6°F) through a complex web of circular causal loops.
- If your temperature drops, sensors in your skin and brain detect the change.
- Your nervous system triggers corrective actions: shivering (muscle contractions to generate heat) and vasoconstriction (narrowing blood vessels to reduce heat loss).
- These actions raise your body temperature back toward the goal.
- If your temperature rises, a different loop is triggered: sweating (evaporation cools the skin) and vasodilation (widening blood vessels to radiate heat).
2. Autopoiesis: Life as a Closed Loop
Going deeper, Chilean biologists Humberto Maturana and Francisco Varela proposed that circular causality is the very definition of life. They coined the term autopoiesis (from the Greek for "self-making") to describe this.
Circular Causality: A Short History (with receipts) | by Maddy Muscari
The final section of the article you've been reading covers this profound idea.
Please read the section "Autopoiesis". Focus on Maturana's core definition: "the parts make the whole, which in turn makes the parts."
An autopoietic system, like a biological cell, is a network of processes that produces the very components that create the network itself. The cell membrane contains the metabolic processes, and the metabolic processes produce and maintain the cell membrane. It's a closed, self-referential, and self-producing causal loop. When this circular organization breaks, the system ceases to exist—it dies. From this perspective, life itself is the ultimate expression of circular causality.
A Unifying Language
This concept provides a powerful, universal language for describing goal-seeking systems, regardless of their domain. The cybernetician Paul Pangaro provides a wonderfully concise summary of this unifying view.
Paul Pangaro | What Is Cybernetics?
In this short clip, Paul Pangaro explains the core cybernetic loop and its application across different types of systems.
Please watch from the description of the fundamental loop. Notice how he describes the exact same pattern—"acting, sensing, comparing to goal"—and applies it seamlessly to technological, biological, and social systems.
As Pangaro illustrates, the walking person, the self-correcting machine, and the participants in a conversation are all engaged in the same fundamental dance of circular causality. They act, sense the effect of their action in the world, compare that effect to a goal, and adjust their next action accordingly.
Conclusion
In this lesson, we have moved from the general notion of feedback to the specific, powerful concept of circular causality. We've seen how this idea breaks from traditional linear models of cause and effect and provides the essential mechanism for all goal-directed and self-regulating systems.
Here are the key takeaways from our exploration:
- Definition: Circular causality describes systems where cause and effect are not a one-way street, but a closed loop where an effect circles back to influence its original cause (A causes B, which influences A).
- A Foundational Concept: The recognition of circularity as a vital, organizing principle, rather than a logical flaw, is a cornerstone of cybernetic thought.
- Engineered Examples: Simple systems like thermostats and electronic buzzers demonstrate this principle clearly in non-living machines.
- Biological Examples: Complex living processes, from maintaining body temperature (homeostasis) to the self-producing nature of life itself (autopoiesis), are fundamentally circular causal systems.
- Universal Principle: The logic of circular causality provides a unified framework for understanding control and communication "in the animal and the machine."
In our previous lessons, we saw that cybernetic systems are goal-directed. Today, we've uncovered the mechanism—circular causality—that makes this possible. In our next lesson, we will delve deeper into the nature of these goals, exploring goal-directed (teleological) behavior from a cybernetic perspective. We will examine how this looping mechanism allows systems to appear "purposeful" without needing a conscious designer dictating their every move.