Two-Dimensional Time: MacBeath's ``Time's Square' and Special Relativity

Murray MacBeath, in his essay ``Time's Square', describes a fictitious scenariowhere various physical observations made by the participants would, he claims, invitethe interpretation that time for them is two-dimensional. In the present paper, however, Iargue that such observations come close to underdetermining the hypothesis of time's twodimensionality;for a rival hypothesis - that, under certain circumstances, the observationscan be explained in terms of the familiar time dilation effects predicted by special relativity- almost fits the evidence as well. That is, under certain (albeit artificial) circumstances theworld can already behave almost as though it were temporally two-dimensional.