Mathematics used to be portrayed as a deductive science. Stemming from Polya (1954), however,
is a philosophical movement which broadens the concept of mathematical reasoning to include
inductive or quasi-empirical methods. Interest in inductive methods is a welcome turn from foundationalism
toward a philosophy grounded in mathematical practice. Regrettably, though, the conception
of mathematical reasoning embraced by quasi-empiricists is still too narrow to include the sort
of thought-experiment which Mueller describes as traditional mathematical proof (Mueller, 1969, p.
295) and which Lakatos examines in Proofs and refutations (Lakatos, 1976). This paper extends the
concept of mathematical reasoning along two further dimensions to accommodate thoughtexperiment.