  By the standards of philosophy, Abstractness has remained relatively uncontroversial. Among the few philosophers to have challenged it are Maddy (1990) (concerning impure sets) and Bigelow (1988) (concerning sets and various kinds of numbers). This relative lack of controversy means that few explicit defenses of Abstractness have been developed.  But it is not hard to see how such a defense might go. Here is one idea. It is a plausible prima facie constraint on any philosophical interpretation of mathematical practice that it should avoid ascribing to mathematics any features which would render actual mathematical practice misguided or inadequate. This constraint makes it hard to deny that the objects of pure mathematics are abstract. For if these objects had spatiotemporal locations, then actual mathematical practice would be misguided and inadequate, since pure mathematicians ought then to take an interest in the locations of their objects, just as zoologists take an interest in the locations of animals. The fact that pure mathematicians take no interest in this question suggests that their objects are abstract.