The Four Operations

Even a primitive membrane created a tiny physical separation, allowing an ion gradient to form. The charge gradient generated a voltage across the membrane, and, as the membrane is an effective insulator, the cell accumulated electric charge.

With a charge difference, you have a work capacity: the cell moved from being a prey of its environment to being an agent that could manage inputs and outputs, inner and outer states.

The early cells went from

• passive diffusion to active harvesting for nutrients and building materials (moving ions from outside to inside through the membrane)
• simple osmotic pressure regulation to active waste management (moving ions from inside to outside through the membrane)
• background noise to active sensing (by detecting ions attached outside)
• Brownian motion to structural state (by detecting ions attached inside)

Early life went from knowing one categorical distinction to learning four primitive operations, single movements across or along the boundary.

Each operation has a starting point and an ending point relative to the boundary. As the single boundary creates exactly two locations, there are only four possible pairs of sources and destinations.

Imagine watching a highly acclaimed dancer. Every one of their moves and steps has a name in the precise vocabulary of dance. Without names, we can’t see the patterns and anticipate what should happen next. Without names, we can’t understand the dance.

If every signal is a piece of information, what happens when a cell receives an ion from outside? It now possesses the information. It knows. When an ion is detected on the outside of a cell, the cell senses it. When membrane tension changes from within? The protocell feels it. When a protocell expels an enzyme to break down food, it predicts the food is there.

The four operations:

• Know: External information internalized across the boundary.
• Sense: External signals detected without crossing.
• Feel: Internal states detected at the boundary.
• Predict: Internal information externalized across the boundary.

At a glance:

The Centipede Test

For each physical distinction, there’s a conceptual category. We started with one: internal versus external. Now we have four new ways to organize ideas.

How do we know we are discovering nature rather than imposing categories? Just as a centipede doesn’t need to understand leg coordination to walk, a protocell knew nothing about signals and information. Every pattern we identify must operate in systems that have zero concept of what they’re doing. If it requires understanding to work, we failed.

But how do we tell if an idea is an idea of knowing or feeling? One question isn’t enough.