Introduction

The introduction presents the main theses of the book and outlines its structure. The positive thesis is that computation is semantic in that it is always accompanied by representations. On the negative side, I suggest that three premises have stood in the way of an adequate account of physical computation: the logical dogma, which asserts that there is a strong linkage between the mathematical theories of computability and physical computation; the architectural dogma, which asserts that the difference between computing and non-computing physical systems has to do, at least in part, with a distinct architectural or functional profile, such as discreteness; and the substantivity premise, which imposes overly strong objectivity, naturalistic, and pancomputationalism-avoidant constraints.