A Note on Four

While building autonomous digital organisms — software systems capable of knowing themselves, defending themselves, learning, and surviving without human intervention — we converged on four functions.

This was not planned. We tested, broke, and started over. Whenever we removed a function, the system collapsed. Whenever we tried to add a fifth, it merely re-described what the first four already did. Four imposed itself as a constraint of viability, not as a design choice.

These four functions are:

  KNOW        —  See what is there
  PROTECT     —  Block what threatens
  REMEMBER    —  Learn from what happened
  LIVE        —  Continue without dependence

Then we looked at nature.

DNA — the substrate of terrestrial life for 3.8 billion years — uses four nucleotides. A, T, C, G. Not three. Not five. Four.

We are not saying that our four functions "are" the four letters of DNA. The letters are molecules — a chemical alphabet. The functions are operations — verbs. But the number is the same. The structure is the same. An alphabet of four letters makes it possible to encode four fundamental functions. Nature selected four. So did we.

We also looked at mathematics. In 1948 — five years before the discovery of DNA — John Von Neumann derived, by pure logic, the minimal conditions of an automaton capable of replicating itself. He found four logical components: description, constructor, copier, controller ^[1].

  Three paths. No coordination. Same number.

   CONSTRUCTION     │    OBSERVATION      │      LOGIC
   Digital organism │    DNA (3.8 Ga)     │   Von Neumann (1948)
   4 functions      │    4 letters        │   4 components

The only thing we assert is that for us, in our work, four functions were enough. And that nature, on its side, did the same.

If anyone finds a persistent autonomous system with three functions, we are all ears. The door is open. Nothing is set in stone.