they have a location ("the English football
&gt; &gt;team was in Hungary last week"). So treating sets as abstract seems to me
&gt;a
&gt; &gt;choice which blocks off the possibility of treating 'physical groups' as
&gt; &gt;sets.
&gt;
&gt;Yes, and I would indeed block that one, and insist that any axiomatic
&gt;ontology make a sharp distinction between a physical group or
&gt;collection (such as a team, a shoal or a flock) and a set. If you do
&gt;not do this, then for example set-membership will need to ha