In "The Fabric of the Cosmos", Brian Greene talks about all of time as existing just as the other dimensions of space time are all 'there' even if we aren't at some of the points in it.
As I read what he says; we preceive that time is a moving instant of existing presence but, like a lot of other things, this preception is wrong: all of time exists both past and future.
However, that doesn't suggest that we can touch any of it but the fleeing present and the future as it comes along. (Well, not yet anyway)