  I discuss some problems related to extreme mathematical realism, focusing on
a recently proposed "shut-up-and-calculate" approach to physics
(arXiv:0704.0646, arXiv:0709.4024). I offer arguments for a moderate
alternative, the essence of which lies in the acceptance that mathematics is
(at least in part) a human construction, and discuss concrete consequences of
this--at first sight purely philosophical--difference in point of view.
