Exploring the Evolution of Complexity: Can Something Become Less Complex Over Time?

When discussing complexity, it is important to recognize that it is a subjective human concept, much like order and disorder. Our perception of order is influenced by our numerical arrangements, while particles in the physical world have no innate numbers or order. Entropy, on the other hand, is a measurable physical feature that describes the distribution and dissipation of energy. Entropy is a fundamental aspect of the universe, yet its origin and evolution remain a significant puzzle.

Entropy and the Natural State of the Universe

According to the principles of physical laws, the universe should naturally move towards a state of thermal equilibrium, which is a state of maximum entropy. However, the universe is far from this state, creating a significant anomaly. If the universe were to reach this state, we would observe entropy decreasing and increasing instant to instant, which would imply a fluctuation in what we perceive as complexity. From our perspective, complexity can indeed decrease, but this is a human judgment rather than a fundamental law of nature.

The Role of Complexity in Closed Systems

Complexity and entropy are distinct concepts. While the entropy of an isolated system must grow over time or remain constant, this law does not apply to complexity. A striking example of this is the Coffee Automaton model, which has been studied in detail by Sean Carroll.

The Coffee Automaton: A Visual Demonstration

Sean Carroll's demonstration through the Coffee Automaton captures the essence of how complexity can evolve over time. The model involves three states of a cup of coffee and cream, which are as follows:

Leftmost Glass: A layer of cream floating on top of a layer of coffee, immediately after the cream has been carefully added. This state has a low entropy, but is intuitively simple. Middle Glass: The situation after mixing has begun. The middle state is the most complex from a human perspective, as it represents a transition between the two extremes. Rightmost Glass: The state after complete mixing, where the coffee and cream are thoroughly mixed. This state has a high entropy, but is also intuitively simple as the resulting mixture is uniform.

In this example, the complexity of the system decreases as the coffee and cream mix, even though the entropy increases. This phenomenon highlights the subjective nature of complexity and its distinction from entropy.

Conclusion

While the natural state of the universe should minimize entropy, human perception of complexity can still decrease as a system evolves. This is because our understanding of complexity is influenced by our mental models and experiences, rather than a fundamental law of nature. The Coffee Automaton model is a powerful visual aid that demonstrates how complexity can decrease over time, even in a system where entropy is increasing.