Zimmerman defends the A-theory of time against allegations of B-theorists that it is in conflict with the Special Theory of Relativity (STR) and the General Theory of Relativity (GTR). He agrees that if there is conflict between the two, then it does indeed cause trouble for the A-theory. The B-Theory of time, holds that the past, present, and future all exist, and are equally real, and there is nothing metaphysically special about the present, nor is it possible to absolutely establish where the present is located. In contrast, the A-Theory of time, distinguishes …show more content…
He notes that it is his disbelief in the existence of past and future objects that drives him to adhere with the presentist view. Relativity’s four-dimensional manifold of space-time points is just a “theoretical entity” (Zimmerman 219) that lives within the context of a scientific theory, it is nothing but a concept, one that a presentist should be free to employ. As a presentist, he can continue conceiving of what exist only in terms of the particular privileged slice that is the present within the 4D manifold. How the future forms will be dependent on what the present is like, and given that the 4D manifold of spacetime points is conceptual, the “important spatiotemporal structure of a straight line in a time-like direction” (Zimmerman 219) can likewise be a line composed of the conceptual points, of where a particle in the present would go, and from where it could have arrived, in the absence of external forces acting upon it. What their status as “conceptual” means is that the presentist doesn’t actually posit these points to exist, but they exist within the context of STR, which he accept as a concept. Since in this reconstruction a straight line running in a time-like direction can be composed, the problem presented by the B-theorists in the paragraph above, becomes largely …show more content…
However, instead of saying that one can justifiably postulate structure that relativity doesn’t consider, as Zimmerman does, Markosian makes a distinction between an “austere” and “robust” versions of STR. Although both are equivalently upheld by empirical findings, the first one doesn’t deny the relation of absolute simultaneity while second does. Since the A-theory requires a relation of absolute simultaneity, the A-theorist would obviously opt for the austere version which supports his line of reasoning. But if he is already dealing with the austere version when STR is presented, then he can deny that relativity entails there not being a relation of absolute simultaneity (Markosian 168). I’m curious how such formulations of STR would actually play out, and if they are actually viable in practice. If they are like the formulations of Lorenz, then their complications will make them short