While not coming from a "mathematics is physics" angle, this bit from "Concrete Mathematics" by Graham et. al. also warns against too much abstraction:<p><i>Abstract Mathematics is a wonderful subject, and there's nothing wrong with it: it's beautiful, general and useful. But its adherents had become deluded that the rest of mathematics was inferior and no longer worthy of attention. The goal of generalization had become so fashionable that a generation of mathematicians had become unable to relish beauty in the particular, to enjoy the challenge of solving quantitative problems, or to appreciate the value of technique. Abstract mathematics was becoming inbred and losing touch with reality; mathematical education needed a concrete counterweight in order to restore a healthy balance.</i>