Dear chakstr, As we usually say : ''it depends..''. In present
case it depends from what you mean by ''No one can do the
same''? Identity relation is pretty complex. ''Relation'' imply
at least two objects. But Wittgenstein stated: '' for two objects
to state that they are identical make no sense and to say that
every object is identical with itself says nothing''. One can
actually state that two ZYX carts are not identical but, hopeful
''equal''. Something like two eggs. I have no idea how two eggs
sound but two ZYX Airy should sound ''equal''. Shame that
postage to Russian Federation is so expensive. Otherwise I
would post my ZYX , retipped by Axel, to you so you could do
the comaprison. Apriori statements like this may impress
Kantians but not Fregean kinds of persons (grin).