pindac , Those are ''deep philosophical waters'' because two
different criteria are assumed. I already quoted Wittgenstein:
''for two things to say they are identical make no sense''.
Even Quine was not able to explain the difference between
equal and identical. Frege's problem to explain truth was
caused by his conviction that ''correspondence'' in correspondence
between an statement and reality make no sense because one
is linguistic and ''the other'' is not. BTW the expression ''extra
linguistic reality'' means ''the same'' . Now ''our carts''. If they are
''identical'' how can they sound different? There are to many people
who sell their Van den Huls but there not many who sell their FR-7fz.
or Takeda's Miyabi.
BTW are Siamese twins equal or identical? If identical what kind
of ID should they have. ? Are two eggs identical or equal in the
sense of their property? Well there is ''property criterion'' and
meaning criterion : ''everything is identical with itself''.
According to Wittgenstein this ''says nothing''. :iucky us humans
each individual has his own such that there are no two with the
same identity. However some may look as an other(grin)