ABSTRACT
The formality condition is companion to the physical symbol system hypothesis (PSSH), namely, a digital computer has the necessary and sufficient means for intelligent action. Arguably, PSSH is the dual claim that human thinking and perception–action are kinds of symbol manipulation and machines can be intelligent. If one’s predilection is to attribute computation to the brain, then the coordination of PSSH and Turing’s thesis forewarns that the brain’s physical structure will prove irrelevant to this attribution. Symbol systems can be constructed from matter, albeit in ways that await full disclosure. In systems satisfying PSSH, the entities over which computations are conducted have two defining properties: They refer to other things and they participate in operations governed by syntax. Conversationally, one can refer to brain as a symbol-manipulating system—that is, conforming to PSSH—on the seemingly reasonable claim that brain does computation.
