[sengstrom]

Stable against what perturbations? What impact would a large body passing through the system have? Stable as in self-correcting (up to a limit)? What is the limit. Even long running accurate simulations of the three body problem are sensitive to perturbations...

[ssivark]

> This system is completely stable—I double-checked with computer simulations. But nature would have a tough time forming this system.

If I understand correctly, I think the author uses "stable" to just mean a _fixed point_. The fixed point must actually be unstable to just about every possible perturbation, which justifies the second statement; if the fixed point were actually "stable" (to perturbations) then it would occur relatively easily in nature.

[petraeus]

I'd imagine each one of the planets would have an artificial gravity generator itself able to correct for gravitational disturbances

[QuantumGravy]

Assuming artificial gravity generators, who needs planets?