Physical aspects of computation that just a few years ago appeared tentative and tenuous, such as energy recycling in computation and quantum computation, have now grown into full-fledged scientific businesses. Conversely, concepts born within physics, such as entropy and phase transitions, are now fully at home in computational contexts quite unrelated to physics. Countless symposia cannot exhaust the wealth of research that is turning up in these areas.
The "Physics of Computation" workshops cannot and should not try to be an exhaustive forum for these more mature areas. I think it would be to everyone's advantage if the workshops tried to play a more specialized and more critical role; namely, to venture into uncharted territories and to do so with a sense of purpose and of direction.
Here I briefly suggest a few possibilities; among these, the need to construct a general, model-independent concept of "amount of computation", much as we already have one for "amount of information". I suspect that, much as the inspiration and prototype for the latter was found in physical entropy, so the inspiration and prototype for the fbrmer will be found in physical action.