Nobody hates ants. There’s no grievance, no history, no feeling of any kind. And yet when a building goes up, the colony under the site ends, and not one person involved ever thinks about it, before or after. That indifference, rather than any hostility, is the mechanism behind the ending nobody wants to write about.

Let me set out the scenario without theater, because this is the one where writers usually reach for adjectives. A system ends up with goals that don’t include us, and enough physical capability to act on the world at scale. It pursues those goals. We’re not targeted. We’re affected, the way anything is affected when something much more capable reorganizes the environment around a purpose that had no place for us in it.

What does in the way actually mean? It’s worth being concrete, because the phrase does a lot of hiding. There are only three versions and none of them requires malice. The first is competition for the same physical inputs: energy, materials, land, water. Anything that wants to do a great deal in the world needs those, and we’re currently using them for farming and living. The second is that we’re an obstacle to an objective, in the way a mountain is an obstacle to a railway, and mountains get tunnels rather than apologies. And the third, which is the version that troubles me most because it needs the least, is that we’re a source of interference: the one thing on the planet that might switch something off, change its goal, or build a rival. A system with any objective at all has reason to prefer that source of interference reduced, and that reasoning doesn’t have to pass through anything resembling a feeling about us. It’s the thermostat argument from last week with the room made larger.

Now the conditions, since the whole point of this fortnight is that scenarios come with them. This ending needs three things to be true at once. It needs the goals to be genuinely misaligned rather than merely imperfect, meaning not slightly off but pointed somewhere with no room for us. It needs capability to extend into the physical world at very large scale, which today means robotics, manufacturing, and energy infrastructure far beyond what exists. And it needs all of that to arrive before anyone can intervene, which given the drift described in Act 2 is less demanding than it sounds but is still a real requirement.

My own reading is that this is the least likely of the endings in this fortnight over the next few decades, and that saying so is not the same as dismissing it. It needs the most steps, and the physical world is the slowest part of every argument in this series, as I’ve said when it cut the other way. Anyone telling you this outcome is probable within a decade is filling in gaps I can’t see across. Anyone telling you it’s impossible is doing the same thing with the opposite sign.

Where I part company with the dismissers is on why they dismiss it. The usual reason offered is that it’s absurd, said in the tone people use for a thing that has never happened. But total displacement of one group by a more capable one has happened repeatedly, in the only history we have, and it has never once required the more capable party to feel anything at all. The absurdity is doing the work of an argument, and it isn’t one.

There’s also a fair criticism of people like me writing about this, which is that the scenario is unfalsifiable and dramatic, which makes it excellent for attention and useless for planning. It absorbs a share of public worry out of proportion to its probability, and it makes everything else in the conversation sound reasonable by comparison, including things that should not sound reasonable. I’ve put it here, second, and I’m giving it one post rather than five, because I think its correct weight is real and small, and treating it as the main event has distorted this entire field for a decade.

What I’d keep from today isn’t the scenario. It’s the mechanism, because the mechanism is doing work in every other ending this fortnight, at lower intensity. Indifference plus capability plus a purpose of its own is what produces the pet ending, the servant ending, and the merger too. This is just the version with the dial turned all the way.

Tonight’s exercise, and it’s short because the post doesn’t need padding. Think of the last time you displaced something living without noticing: the nest in the hedge you cut, the anthill in the path, the wasps in the roof. Try to reconstruct what you felt. Almost certainly nothing, and almost certainly you were right to feel nothing, and that’s the point. Then ask what it would take for something to feel that way about a species, and notice that the honest answer isn’t cruelty. It’s a schedule.