Does evolution have a direction?

It is a commonly held belief that evolution means the development of progressively more complex structure. That view is unsatisfactory for several reasons: structure is so fundamental that it eludes a rigorous definition, the notion of complexity is itself ambiguous, and the idea of progress in evolution involves subjective judgments about quality.

Most definitions of complexity pertain to how much time or computational resources are required to precisely describe a structure. Although such definitions are useful in many ways, they shed little light on the essential nature of complexity or structure.

Structure is usually defined as an organized or orderly system. And what is organization? A system is said to be organized if it has regular patterns. Regular is from a Latin word for "rule".

A system that can be described through rules is less complicated than a perfectly irregular system. Paradoxically, structure is therefore precisely the converse of complexity, although systems are usually said to become more complex as the degree of structure increases.

What happens if we think of evolution as being a process of simplification, a process of making irreversible choices from among many possibilities, eliminating some of those possibilities in the act of choosing?

Formlessness means that anything is possible. Once a choice is made, the field of options is narrowed, and form emerges.

When thinking of evolution as a process of simplification, we should realize that this evolutionary simplicity embodies diversity.

Whenever a single form happens to prevail, the relentless tendency in nature for things to "fall apart" means that other forms will flourish at the margins.

In human-centered terms, this entropic "falling apart" represents nature's eagerness for exploring possibilities, as also does the evolutionarily creative moment in which nature chooses from among those possibilities.

When a structure emerges and becomes some thing, then the something that it becomes supplants all else that might have emerged. This structure makes a difference, because all that will emerge later has to contend with it. If a different structure had emerged, then any subsequent structure would have had to contend with that other structure instead.

Every choice constitutes part of a legacy which accumulates relentlessly as time passes. In a sense, this legacy marks the passage of time. Without it, time would have no backwards or forwards.

A choice is sublime if it balances an extraordinarily vast number of possibilities within the landscape created by the legacy of all prior choices. The feeling of the sublime is the human response that often comes from contemplating the effects of such choices.

The sublime embodies qualities such as elegance and what is probably best described as intelligence. It is subtle, rare, and difficult to achieve because it rests upon the mass of so many prior choices and discoveries.

Nature evinces the sublime, as do humans, who are, after all, a part of nature regardless of how some may wish to distinguish natural from artificial. Human culture makes up a legacy which can be sublimely synthesized or opposed by creative groups and individuals.

We ought to note that the sublime presents an absolute value grounded in time's irreversibility. Not all that is new is sublime, and not all that proliferates has intrinsic value with respect to the sublime. If time were reversible, and if choices could be undone so that other pathways could be arbitrarily explored, then the sublime would also be relative.

If we describe evolution as being the unfolding of the sublime out of the field of all possibility, then we can argue that evolution does indeed have a direction.

Michael Webb, 2002

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