Are Human Beings with Extreme Mental Disabilities and Animals Comparable? An Account of Personality

Abstract

The concept of personality is one of the most difficult issues in modern and contemporary philosophy, specifically when we reflect on whether human beings with extreme mental disabilities (e.g. those with Alzheimer’s disease or in persistent vegetative state) are endowed with human nature and personality. This paper will examine two different philosophical views in order to respond to that question. First, we will analyze Kant’s Groundwork of the Metaphysics of Morals, according to which personality can be denied to human beings with extreme mental disabilities, although we will argue that it is possible to have a more inclusive interpretation of the Groundwork, based on the connection of the concepts of human nature, dignity, rationality, autonomy and personality. Secondly, we will discuss Peter Singer’s contribution. In some of his works, he argues that the concepts of rationality, dignity and equality are not extensible to beings with extreme mental disabilities, since they do not have a morally relevant life. In his opinion, the status of this group of beings should undergo a thorough revision. If this revision were carried out, i.e., if the philosophers reflected on the personality of beings with extreme mental disabilities, they would – according to Singer – most likely have to face their own speciesism related to the status of non-human and non-rational beings. In order to broach the controversy, we will draw on the concepts of numerical and qualitative identity, and we will make a critique of Derek Parfit’s psychological view about identity. If we, following Kant, admit a necessary conceptual philosophical distinction between, on the one hand, what a human being is and, on the other, what the concept of a moral person means, we can make a critique of Parfit’s and Singer’s positions. In doing so, we hope to make a strong case for the claim that beings with extreme mental disabilities have a human and rational nature, and therefore deserve the status of persons.