FOM: difference, structure, congruence

[Vaughan Pratt]

Re Bill Tait's laconic comment on Leo Harrington's fascinating post, my
first reaction was "Et tu, brute?"  But then I decided it was about right.

Actually I was following Leo right up to the end (but then I followed
Sokal right up to the end too).  But then Leo closes with

>to get a foundation for the existence of things one might be
>led to emphasize differences over congruences since differences are
>what one ultimately points to when invoking existence.

Mind rephrasing that, Leo?  Best I could come up with was "doubletons
exist but singletons don't," which is how I understood the ancients to
regard numbers---what's the point of counting a singleton?

Reason I ask is that the context seems to make me the singleton and Steve
the doubleton.  It would disturb me to cogitare Steve est et non sum.

Vaughan Pratt