 Another objection is that the social as well as the medical model both rest on a false dichotomy between biological impairments and social limitations. There are two versions of this objection. One maintains that disability is a complex phenomenon, in which biological impairment and social exclusion are deeply interwoven and difficult to tease apart (Martiny 2015; Anastasiou &amp; Kauffman 2013). The other version of this objection rejects the treatment of impairment as a (strictly) biological phenomenon. “Impairment”, the argument goes, is no less a social construction than the barriers faced by people so classified (more on this below). Claims that there is a stable biomedical basis for classifying a variation as an impairment are called into question by shifting classifications; by the “medicalization” of some conditions (shyness) and “demedicalization” of others (homosexuality). Moreover, the social environment appears to play a significant role in identifying and, arguably, in constituting some impairments (dyslexia) (Cole 2007; Shakespeare 2006; L. Davis 2002: Ch 1; Tremain, 2001, 2017; Amundson 2000). What counts as an impairment may depend on which variations appear to be disadvantageous in familiar or salient environments, or on which variations are subject to social prejudice: Less-than-average height may be more readily classified as an impairment than greater-than-average height because the former is more often disadvantageous in environments designed for people of average height, or because it is generally seen as less desirable. For such reasons, it is difficult to establish the objectivity of the impairment classification by appeal to a clear and undisputed biomedical norm. Amundson (2000), indeed, goes so far as to deny that there is any biological basis for a concept of functional normality—a claim emphatically rejected by Boorse (2010).