I, as others before me have stated, have a paltry understanding of the philosophical underpinnings of this thread, however, if I could offer some simple definitions, which may or may not be useful by others' reckoning, but which I have seen stated numerous times in the subject literature:
Formalism:- School of thought suggesting mathematics is 'invented'
Platonism:- School of thought suggesting mathematics is 'discovered'
The most interesting views that I have come across regarding the subject are those of Stephen Wolfram, as expounded in a video I have posted previously:
http://www.closertotruth.com/video-profile/Is-Mathematics-Invented-or-Discovered-Stephen-Wolfram-/1384
His suggestions are all the more riveting considering the seemingly 'objective' viewpoint he has taken on the subject of mathematics, and the years he has spent studying this topic, if you will, from the 'outside'.
Now, regarding whether or not I understand his conclusions is another matter.
His initial statements, that our mathematics is an 'artifact', a product of human culture, and hence (as others have posited) would be, in some ways, markedly different from extraterrestrial 'mathematics' is, at first glance, Formalist.
However, all this argument apparently does is to push the debate back a 'step'. The 'Universe of Possible Mathematicses' which he introduces, could be thought of as Platonic in nature. Or, at this stage, with a sufficiently general definition of mathematics as a formal system composed of an arbitrary string of symbols, is the question of Formalism vs. Platonism defunct?