  Nevertheless, the nature of the (in)justice of limitations associated with physical or cognitive impairment remains a concern in the philosophy of disability, including feminist disability theory. Biological difference is a central and undeniable fact of disability, but the impact of biology on the kinds of experiences characteristic of being disabled is much more controversial.  There is debate as to whether the functional limitations associated with disability result mainly from biology's going awry and whether, if disability is disadvantageous, it is naturally and immutably so. Or instead whether disabled people's functional limitation should be laid at the door of flawed social practice which rewards the species-typical functioning of so-called normal people and punishes the anomalous functioning of disabled people (Wendell 1996). 