TODO

All self-replicating structures are primarily focused on self-replication. This is because every action requires energy, which is a finite resource. Any action that does not increase the structure's fitness ¹⁾ therefore is *decreasing* the structure's fitness. Organisms with decreased fitness are then bred out.

Speaking more specifically, all organisms are constantly working on creating more copies of themselves. How does the organism “know” how to do this? Evolution has made several approaches, which I will categorize into two categories. The first category of organisms are organisms that don't know anything. Instead, the physical structure of the organism lends itself to reproduction. Plants and Fungi fall into this category. The other category contains organisms that are programed with several “switches” that either punish or reward certain actions or events. Rewards are doled out for actions that move the organism closer to reproducing, and punishments for actions that move it further away. All animals fall into this category, and the swtiches are inside the animal's brain.