Would a siphon work in zero G conditions? Has this ever been tested in space? If the atmospheric pressure theory is correct the siphon should work in the zero g artificial atmosphere of a spaceship. If not, then one can only conclude that gravity is the culprit.
No, I don't believe anybody would say that a siphon would work in zero G, because you do need gravity to lower the water in the long leg of the siphon to create the lowered pressure above the short leg of water.
What the good Professor is claiming is that a siphon would work in the presence of gravity, but in the absence of any atmospheric pressure (vacuum.)