A question about physicalism/materialism

[wazz]

Logical rules would still be true in the absence of reality (whatever that means), and so mathematical rules derived from logical truths would still hold. The mathematical rules wouldn't really be of any use, though, as they wouldn't have anything to describe, so e and pi would be meaningless.

To answer the OP, physics is not based on maths or logic, it's based on (for want of a better description) the rules of reality. It just so happens that they coincide quite nicely with certain man-made mathematical constructs.