Unconventional Computer Programming

Classical computing has well-established formalisms forspecifying, refining, composing, proving, and otherwise reasoningabout computations. These formalisms have matured over the past70 years or so.Unconventional Computing includes the use novel kinds of sub-strates – from black holes and quantum effects, through to chem-icals, biomolecules, even slime moulds – to perform computationsthat do not conform to the classical model. Although many of thesesubstrates can be “tortured” to perform classical computation, this isnot how they “naturally” compute.Our ability to exploit unconventional computing is partly ham-pered by a lack of corresponding programming formalisms: we needmodels for building, composing, and reasoning about programs thatexecute in these substrates. What might, say, a slime mould program-ming language look like?Here I outline some of the issues and properties of these uncon-ventional substrates that need to be addressed to find “natural” ap-proaches to programming them. Important concepts include embod-ied real values, processes and dynamical systems, generative systemsand their meta-dynamics, and embodied self-reference.