Pointy endpoints and internal space and time

In a series of recent posts, starting with this one, I argued that relativity theory gives us good reason to think that at the start and end of our lives we are pointlike in spatial extension. Crucial to these arguments was the idea that there is no privileged reference frame.

The conclusion is, of course, rather counterintuitive. While it is plausible that we start as a cell and that we shrink with old age, in neither case are we pointlike.

However, in some earlier posts, like this one, I explored the idea that substances may have internal space and internal time, in addition to the external spacetime of the universe.

Here is a suggestion that could save the intuition that we are not spartially pointlike at the beginning and end of life. We have internal space and time, and our internal space and time has an absolute simultaneity relation. With respect to internal time, at the first and last moments of our lives (I’m simplifying by assuming there are such moments), we have significant non-pointlike spatial extension. Of course, most external frames of reference do not agree with our internal simultaneity relation, and in most of them, we are pointlike at the beginning and end of our lives. But that’s fine: our intuition relates to our internal space and time.

The above suggestion is inspired by Rob Koons’ suggestion that our rest frame could be the privileged frame with respect to which we could have spatially non-pointlike endpoints of life. That suggestion doesn’t work for the technical reason, which Koons also noted, that there doesn’t seem to be a well-defined notion of a privileged frame of a squashy organism. (One might try to go with the rest frame of the center of mass. But an organism’s center of mass can move faster than light—e.g., in a fast amputation. And faster than light motion doesn’t define a reference frame.) But even if there isn’t a well-defined rest frame, there is a family of “approximate rest” frames that are intuitively close to what we would expect the rest frame to do. And then we could suppose that the internal simultaneity relation is pretty close to these approximate rest frames.

Note that we should not expect the internal simultaneity relations to align neatly between substances (except in the special case of substantial change where we might reasonably suppose that the old substances’s later internal simultaneity relations approximate the new substance’s earlier ones), and hence they do not define a global privileged simultaneity relation that would threaten relativity theory.

So now I think that my argument about spatially pointy endpoints of life gives us a choice between three options:

1. Accept spatially pointy endpoints.

2. Accept a global privileged reference frame.

3. Accept privileged reference frames specialized for individual substances.

In the last option, I think the best way is the way of internal space and time, but I suppose one could also think there are privileged external reference frames specialized for individual substances.

Accepting privileged reference frames specialized for individual substances could also help materialists deal with the problem of the unity of consciousness for a spatially extended brain.