Gualtiero Piccinini articulates and defends a mechanistic account of concrete, or physical, computation. 
    A physical system is a computing system just in case it is a mechanism 
    one of whose functions is to manipulate vehicles based solely on differences 
    between different portions of the vehicles according to a rule defined over the vehicles. 
    Physical Computation discusses previous accounts of computation 
    and argues that the mechanistic account is better. 
    Many kinds of computation are explicated, such as digital vs. analog, serial vs. parallel, 
    neural network computation, program-controlled computation, and more. 
    Piccinini argues that computation does not entail representation or information processing 
    although information processing entails computation. 
    Pancomputationalism, according to which every physical system is computational, is rejected. 
    A modest version of the physical Church-Turing thesis, 
    according to which any function that is physically computable is computable by Turing machines, is defended.