 A ‘machine table’ describes a machine if the machine has internal states corresponding to the columns of the table, and if it ‘obeys’ the instruction in the table in the following sense: when it is scanning a square on which a symbol s1 appears and it is in, say, state B, that it carries out the ‘instruction’ in the appropriate row and column of the table (in this case, column B and row s1). Any machine that is described by a machine table of the sort just exemplified is a Turing machine. (Putnam 1960/1975a, 365; cf. also Putnam 1967/1975a, 433–4)