ne can (and I seem to recall some papers on this point) take
&gt;the non-standard view that the 4-D extension is an attribute/property of the
&gt;object, then you can maintain the distinction - but lose the principle of
&gt;identity. In this case, two things (of different types - following Locke)
&gt;can occupy the same 4-D space-time.

Yes, this is one way to do it, and one has to give up on what might 
be called 4-d mereological criteria of identity, I agree.  But then 
much of the perceived clarity and u