The real price of the dead past: a reply to Forrest and to Braddon‐Mitchell
David Braddon-Mitchell's recent paper begins, 'Many philosophers have found a theory of time that shares features of four dimensionalism with an account of the genuine passage of time to be attractive' (2004: 199). I was once one such philosopher. But then I read the rest of BraddonMitchell's paper and was convinced that this combination of views is untenable.' It implies that it is almost certainly not now now.2 Braddon-Mitchell's particular target is the Growing Block Theory, according to which the past is real, the future is not, and the present is to be identified with that hyperplane of space that is the leading edge of the growing four-dimensional block that is our universe. If the Growing Block Theory is true, then we have no reason to think that this moment, the moment we are all in right now, is the present moment. For all we know, some moment in the thirty-seventh millennium is currently at the leading edge, and so it is the real present, you and I being ancient history. Our evidential situation is no better than the current one of Caesar, crossing the Rubicon in 49 Bc, believing falsely that he is doing so in the present. But (to conclude the argument) scepticism about whether one exists in the present is absurd. Any view that allows such scepticism is unacceptable. Braddon-Mitchell considers a way, due to Peter Forrest (forthcoming), for the Growing Block Theorist to stop this argument: the Dead Past Hypothesis. According to the Dead Past Hypothesis, life and consciousness are 'by-product[s] of the causal frisson that takes place on the borders of being and non-being' (Braddon-Mitchell 2004: 201). On this view, only those beings on the leading edge of the universe, and so in the objective present, can be conscious and living. The Growing Block Theorist can then block the road to scepticism by deriving knowledge that one is in the present from knowledge that one is conscious. We are different from Caesar because he's now a Zombie and we're not.