 Vector knew that the sinking land bridge idea would violate isostasy and so he thought that the continents probably did actually move apart from each other and his mechanism for how this would work as shown in this little sketch here where you've got continents, you know here's two of them, and some seafloor and he actually thought the continents would somehow plow through the seafloor and because you have the mantle as viscous. Now the problem with this is that the frictional resistance that you'd encounter pushing a giant continent over the ocean floor is enormous. Think of trying to push a carpet across your floor just by shoving on one end of it. You'd never be able to do it, it wouldn't work. And not only that but but his idea that maybe solid earth ties is the thing that would drive this. It didn't really work either because some other geophysicists like Harold Jeffries could calculate that if solid earth ties were strong enough to move continents then actually the earth's rotation would stop in less than a year and also mountains would probably collapse under their own weight. So geophysicists knew that his model wasn't going to work but they basically just dismissed the fact that the contracting earth hypothesis had a bunch of internal contradictions and it couldn't work either. And so it's a little bit surprising actually that nobody kept hammering about this, I think. Arthur Holmes actually proposed around about the same time that convection in the mantle could drive continents to move. And that's actually not so far wrong from the way we picture today but it's interesting that nobody ever took that idea and ran with it either.