I'd say that you can't have computation without physics. I am willing to bet that it'll eventually be proved that computation is inherently a physical process: information is just one form of energy, and computation is the process of converting energy and entropy into information. Computer Science is then best viewed as a subset of Physics.

If I could study ANYTHING without worrying about getting funding, I'd study computation as a physical phenomenon. I think the answer to P vs NP lies somewhere in the laws of physics; solving NP-Complete problems in polynomial time on the size of the problem input is either possible in our physical universe, or it is not.