In 2020, scientists identified a tiny, worm-like fossil in Australia named Ikaria wariootia. The size of a grain of rice, it dates back 590 million years. It lacked legs or eyes, but it possessed the fundamental bilateral blueprint: it could burrow through the seafloor with intent, using muscles to move toward organic matter. This species, or one like it, is the common ancestor of the tiniest tardigrade and us.

Your agency has deep evolutionary roots, and in a real sense, this is the start of it. A forward-driven body, moving through time and aimed into the world.

The bilaterian split marks the evolutionary divergence where organisms moved away from radial symmetry (like jellyfish or sponges) and developed bilateral symmetry—a distinct front, back, left, and right. This is when life transitioned from a passive to active state: from  being to doing. This “idea” made complex life possible, transforming animals from passive drifters into active, goal-oriented hunters and foragers, and from proto-agency to agency.

Directional movement requires a command center. The concentration of nerve cells into a head is called cephalization, and is the origin of the brain. From here, agency becomes increasingly organized as animals develop a through-gut (a mouth-to-anus digestive tract).

Mental and physical agency evolved together and are a good example of a coevolutionary feedback loop. Whether two traits or two species, coevolution directs and accelerates: predator and prey come to mind. This was early reciprocal coevolution: increasingly directed locomotion leads to an increase in sensory abilities, and the evolution of the brain. More body control makes better processing valuable; better information then makes more sophisticated movement valuable. Neither has to come “first” in any strong sense. Evolution kept ratcheting both.

If the history of life is a book, this is the start of the chapter on “Will.”