Light Rays and Black Holes II - Edward Witten 

The joke is that strong subadditivity is relatively obscure, as it is a not easily visualized relation on the subentropies of three subsystems, while cosmic censorship is completely intuitive (you can see why gravitational singularities should have to hide behind horizons), so this is making an analogy from the more obscure statement to the more clear statement, which is the opposite direction from how you are supposed to make analogies. It's like if I said "Walter White in Breaking Bad transforms like a string heated past the Hagedorn temperature." That's an analogy any reasonable human being would expect to be made the other way. So it's funny. Witten makes this counterintuitive analogy nevertheless because the strong subadditivity is proved mathematically, and therefore 'obvious' mathematically in a way that the Penrose censorship conjecture, which is unproved, is not. Regardless of the fact that in human physical intuition it's the other way around. It's not ever easy to precisely state the censorship conjecture, let alone prove it in the rigorous sense, because even the Navier Stokes equations might be singular, so would a singularity in Navier Stokes on a gravitational background count as a disproof of Penrose's conjecture? Obviously not.