Circulus in probando
After a week of almost no TV, yesterday we spent some time catching up (thanks, TiVo). In the morning, we caught a Colbert Report. They were doing a bit on Stephen Hawking, and said that he was the Lucasian Professor of Mathematics at Cambridge, "a position once held by Isaac Newton." Later on, we were watching a Nova on Isaac Newton and it said he became the Lucasian Professor of Mathematics, "a position now held by Stephen Hawking."
So, each physicist's provenance is that he holds a chair held by the other. Personally, I'd say that it does a lot more for Stephen Hawking's reputation than it does Isaac Newton's, but that's just me.