Sidebar 1:
In the perfect GA world, replication must be almost counterbalanced by mutation and crossover. Replication sucks the heat from the system and remorselessly forces it towards crystallization and stasis. Mutation and crossover do the opposite, generating a vital warmth that keeps the system fluid and dynamic. Too much heat causes the system to boil chaotically; too little heat causes it to crystallize uselessly. However, just the right amount of heat enables its thick, logical fluid to mold itself to the landscape as it flows gently downhill.