I'd say that yes, Math being Philosophical is a matter of convention, you're right.
However, its not hard to prove that Math is Philosophical either. Math is derived through Linguistics and is Epistemic in nature. We can not start from Induction and get to Math. We must start from Math and get to Induction. So, basically, in our basic format we first know that Linguistics is the beginning and starting point for all items. Formal and Informal Logic is first derived from the self evident first principles of Logic. However, Math is expressible in terms of Language! So, therefore, we can define all Mathematical terminology. For instance, the number one has a definition, the number two has a definiiton. We can also state that two plus two equals four. So we derive math from Linguistical Analysis. Therefore, we have a surefire way to denote that we move from Informal and Formal Logical Premises to Math, which is derived as Symbolic Logic, and is the third step on the ladder of the Science of Inference.
Edited by Casey Powell, : No reason given.