Theme introduction
Introduction to Theme II
Biological continuity never reproduces an identical order. Variation enters replication and development, exposing living forms to environments whose conditions preserve some differences, eliminate others, and alter the effects of traits across generations.
Chapter 4 treats error as a source of variation capable of opening new possibilities; Chapter 5 separates natural selection from any image of choice or evaluation; Chapter 6 then examines adaptation as a local compatibility between organism and milieu, effective under particular conditions and vulnerable when those conditions change.
Complexity emerges here through a history without foresight. Selection filters material differences after they occur; it does not anticipate the forms that will endure. Adaptation consequently carries the contingency of every encounter that produced it, giving life workable arrangements without granting any organism a final or universally superior form.
Theme chapters