That the 8 classical planets are qualitatively different than Pluto and the other large bodies in the Solar System, precisely because they dominate their orbits. The conclusion of the paper was that it was sensible to have only 8 planets.

This was a few years before New Horizons, I think, so I guess his opinion changed.

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"Barbarism is the natural state of mankind. Civilization is unnatural. It is a whim of circumstance. And barbarism must always ultimately triumph" -- Conan