 Nonetheless, there is something important that is thought to distinguish humans from non-humans that is not reducible to the observation of behavior best explained by possessing a certain capacity and that is our “personhood”. The notion of personhood identifies a category of morally considerable beings that is thought to be coextensive with humanity. Historically, Kant is the most noted defender of personhood as the quality that makes a being valuable and thus morally considerable (for a contemporary utilitarian discussion of personhood, see Varner 2012).  Kant writes: