[mannykannot]

This should be seen in the context of the article Yudkowsky is replying to. Collet's position is that runaway AGI is impossible, and in support of that, he claims that it is impossible for AI technology to grow super-linearly. In his refutation, Yudkowski has merely to show that it is not beyond the bounds of possibility.

Of course, insofar as he is also putting forward the view that the risk is significant, he is also putting forward the opinion that it is quite plausible - at least plausible enough to take the scenario seriously. That argument can survive occasional stalls in the rate of technological advance, if that is indeed what we are seeing.

[goatlover]

So the real question is about plausibility, not possibility?

It's possible that predatory aliens will show up on our doorstep sometime in the next few decades. But it's not very likely, and not something we need to prepare for.

[mannykannot]

By claiming the impossibility of an AI apocalypse, Chollet attempts to avoid discussing any other possibility / plausibility / likelihood than zero, but claiming impossibility brings with it a burden of proof that his arguments cannot carry.

As to whether an AI apocalypse is more or less likely than an invasion by predatory aliens, I would guess that it might be the more likely one, but I wouldn't put much effort into defending that position.