are, have been or will be. Then this is a physical object,
&gt;however it has a uninteresting, useless location and weight (particularly
&gt;if
&gt;we take it as extended over possible worlds). This seems to me to show that
&gt;the issue about spatio-temporal location (and weight) is more linked to
&gt;usefulness and ease of determination, rather than the nature of the things
&gt;itself.
&gt;Pat Hayes wrote:
&gt;There is a pretty well-investigated subject area of formalisations of
&gt;the notion of 'part', 