Evolutionary Restrictions

General Remarks on Evolutionary Restrictions

The final category of answers to the EOC focuses on the fact that there are certain limitations in what evolution can do. Using the “great engineer” metaphor, we may say that we can hope to achieve certain things with our ham-handed tinkering that stumped evolution, because we have access to tools, materials, and techniques that the great ingenious engineer lacked.

Metaphors aside, we can identify several restrictions of evolution’s ability to achieve fitness-maximizing phenotypes even in the EEA. These are important, because in some cases they will indicate clear limitations in the “wisdom of nature” and a fortiori cases where there is room for potentially easy improvements. At a high level of abstraction, we can divide these restrictions into three classes:

  • Fundamental inability: evolution is fundamentally incapable of producing a trait A.
  • Entrapment in local optimum: evolution is stuck in a local optimum that excludes trait A.
  • Evolutionary lag: evolution of trait A takes so many generations that there has not yet been enough time for it to develop.

These three classes, which are discussed in more detail in the following three subsections, are not sharply separate. For example, one reason why a trait may take a vast number of generations to develop is that it requires escaping from one or more local optima. And given truly astronomical timescales, even some traits that we shall regard as fundamentally beyond evolution’s reach might conceivably have evolved. However, the three classes are distinct enough to deserve individualized attention.

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