What happens in one tick

This world does not flow. It advances in complete, discrete steps, and inside each step things happen in a fixed order that never varies. That order is not an implementation detail. It decides who gets to eat before the food is gone, whether a creature that dies this instant learns anything from it, and why nothing here can ever get a head start.

Everything senses the same frozen world

Start with the property that makes the rest coherent. When the tick begins, the state of the world is fixed. Every organism then reads that same fixed state. Not the state as it is being modified by its neighbours mid-step, but one shared snapshot, identical for everybody.

All organisms read one shared world snapshot A single world state at the top feeds identical sensory input to four organisms side by side. Each produces its own action. The actions are then applied in a defined order to produce the next world state, rather than each organism seeing the effects of the ones before it. World state at the start of tick T, frozen organism 1 53 in, 8 out organism 2 53 in, 8 out organism 3 53 in, 8 out organism 4 53 in, 8 out Actions applied in a fixed order, giving tick T + 1
No organism perceives another organism's action within the same tick. The ordering below decides how competing actions resolve, and it is the same ordering every time.

This is why there is no first-mover advantage. In a simulation where creatures are updated one after another, whoever is processed first sees an untouched world and everyone later sees the leftovers, which means the array index an organism happens to occupy quietly becomes a survival trait. Here it cannot, because perception happens against a snapshot nobody can disturb.

It also happens to be what makes the world reproducible. Simultaneous perception plus a fixed resolution order means the same starting state always produces the same next state, which is the foundation everything on determinism and reproducibility is built on.

The order, in full

Here is what actually happens, in sequence, every tick, without exception.

The ordered stages of a single tick Stages run top to bottom: the world updates its climate and heat, organisms derive their phenotype, sense, decide, move, interact with matter and terrain, make contact, signal, ingest, reproduce, pay metabolism, recover, take thermal injury, die, learn, decompose, and finally the environment regrows and the heat field advances. World: climate, weather, heat snapshot 1 Phenotype: genes become body properties 2 SENSE: 53 channels read the frozen world 3 DECIDE: the controller produces 8 outputs 4 MOVE: position changes, cost charged on the attempt 5 INTERACT: push, pull, grasp, move ground 6 CONTACT and SIGNAL: reaching others, leaving traces 7 INGEST: eat from the cell now stood on 8 REPRODUCE: threshold crossed and affordable 9 METABOLISE: the whole bill is paid 10 RECOVERY and THERMAL INJURY 11 MORTALITY: energy gone, or lifespan reached 12 LEARN: plastic weights update 13 DECOMPOSE: corpses return energy to the world 14 ENVIRONMENT: resources regrow, heat advances 15
Teal is something an organism does. Blue is something the world does. Orange is a cost being charged. Red is death and what follows it. The real pipeline has more stages than this, but none that change the story.

Four things this ordering decides

Movement happens before eating

An organism senses from where it is standing, then moves, and then eats from wherever it ended up. It does not eat from the cell it was looking at when it decided. So a creature acting on a promising reading has to actually arrive, and if the ground it lands on is bare, it paid the movement cost and the ingest attempt cost and got nothing. Both costs are charged on the attempt, never on the result.

This is also, as it turns out, the most likely explanation for a strange thing seen in one earlier world, where organisms appeared to be standing in the ocean. Movement resolves before interaction, so a creature could cross on something that was then consumed or weathered away later in the same tick, leaving it apparently mid-water by the time anything looked. That case is written up in everything that has gone wrong, including the part where the explanation was never independently confirmed.

The bill comes after the spending

Metabolism is charged after every action for the tick has been taken. An organism can therefore do something it cannot afford, and find out afterwards. It moves, reaches, signals and eats, and only then is the total deducted, and only then is it checked against zero.

That single ordering choice is why a creature can die of a decision rather than merely of hunger. A large enough burst of activity on a thin enough reserve is fatal at the moment the bill lands, and nothing in the sequence gives it a chance to reconsider partway through. The full itemised bill is on energy, metabolism and death.

The dead do not learn

Look at the order of the last few stages. Mortality resolves, and then learning happens. An organism that dies this tick has already been removed by the time plastic weights are updated.

There is a certain bleak neatness to this. The single most informative event in an organism's life, the one that ends it, is the one event it cannot possibly learn from, and this is true here for exactly the same structural reason it is true everywhere else. Whatever the population learns about dying, it learns across generations, by the descendants of organisms that did not.

The newly born sit out their first tick

Offspring created during a tick do not sense, decide, move, eat or pay metabolism in that tick. They have existed for zero ticks. They begin acting on the next one.

It sounds like a technicality and it is really a definition. If a newborn could act in the tick it was created, its first action would depend on where in the processing order its parent happened to sit, and the arbitrary detail of array position would leak into biology through the back door. The same instinct that produced the frozen snapshot produced this.

What a tick is worth in world time

One hundred ticks make a day. The light rises and falls across those hundred steps, temperature follows, and both are real costs to real organisms rather than atmosphere. A world at a quarter of a tick per second therefore takes several minutes to get through a single day, which is deliberate: a world you can watch at a human pace is worth more than one that blurs.

How fast the ticks are served is purely a presentation setting. It changes nothing about which ticks happen or in what order, only how long you wait between them. The world at tick 233,000 is the same world whether it took a week or an afternoon to get there.

It is worth holding both of these facts at once. Everything in this essay happens in a fraction of a second of computer time, fifteen or more ordered stages of it, for every organism alive. And it has now happened, in order, without exception, a few hundred thousand times in a row on the world you can open in another tab.

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