[FOM] the stuff that [numbers] are made of

[charles silver]

To me, the sort of issue of what numbers "really are"
is explained nicely by concepts in computer science, 
where an abstract data structure (sometimes called
an abstract data type) is realized by implementing
one of many isomorphic copies of the structure.  The
actual details of the underlying implementation are 
said to be "encapsulated" or just hidden, as they don't
matter as long as the desired properties are realized.  

  Thus, asking what an abstract data structure "really is"
in terms of its implemented constructs isn't even a
meaningful question.  I think the same may be true
of the corresponding question about what numbers
"really are."

Charlie Silver