Here, the past itself may not be an actual infinity since it still only exists one moment at a time, at least in our way of talking about it, but the number of past moments certainly is.
Our way of talking about it is not necessarily correct. It may not only exist one moment at a time -- the past could still be with us. Are you familiar with the "Growing Block" theory of time? In that theory, time is actually a
spatial dimension. Our familiar 3-D world is a surface moving along the 4th dimension. The 4-D world has a boundary, and new 4-D stuff is continually added to it at the boundary. What would look from the outside like a growing 4-D object looks from within the surface like a lot of 3-D objects moving around in 3-D.
I'm not familiar with it but I have definitely heard of it.
I would say that you'd need to decide how much time is now a spatial dimension. Given what you're saying, I take it that time is somewhat like space in that the whole of the past would keep existing. Yet, it wouldn't be entirely like space in that things could still "grow", "move", "be added", which presumably would require something like ordinary time. So, I would question this notion that time would be like space.
Rather, we could take the Growing Block theory as saying that time is just like we ordinarily think of it but that our 3D-world as it has existed in the past is preserved, as you described, along a 4th spatial dimension. So, the 3D-surface of our world would indeed be "growing", which now is OK since we've kept time just as what we ordinarily think of it. That doesn't necessarily make any difference but it seems a simpler way to look at it. And the past could still be either finite or infinite.
Alternatively, you don't need to say that, in this theory, "time is actually a
spatial dimension". It would still be a time dimension, but then the past wouldn't "actually" exist for us in the present. It would just still exist in the past. But, well, that's wouldn't sound so different from our ordinary view!
Or another way to look at is, rather than the whole 4-D world ending at the boundary surface, there's a 4-D object embedded in 4-D space, with a phase change happening at its surface. The past is a solid object; the future is a liquid; and the solid block is growing because the liquid at its surface is freezing. What we perceive as 3-D objects moving around in 3-D, a 4-D outside observer would perceive to be the end-points of 4-D defects in the crystal structure of the object, propagating in various directions along its growing 3-D surface, as new material freezes onto the object.
Right, same remark, but this one is entirely new to me. Interesting.
And maybe it could explain inflation, including the slowing down of it. Maybe more than four dimensions would be required.
The point being, if time works that way and there has been an infinity of past moments, then the universe currently contains an actual infinity of past states, a complete permanent record of the past, frozen solid, extending out from here along the 4th dimension of space.
It certainly seems to work in the abstract but that's a bit difficult to reconcile with our notion of time. My interpretation of this perspective goes back to our ordinary notion of time. It also keeps this notion that the past is preserved, but along a 4th spatial dimension, not a time one.
Still, I don't have any objection to this idea.
I'm just trying to figure out how consciousness could fit into this picture.
Unless, our notion ordinary of time is indeed preserved.
EB
