ens rationis (Latin ‘a being of reason’), a thing dependent for its existence upon reason or thought; sometimes known as an intentional being. Ens rationis is the contrasting term for a real being (res or ens in re extra animam), such as an individual animal. Real beings exist independently of thought and are the foundation for truth. A being of reason depends upon thought or reason for its existence and is an invention of the mind, even if it has a foundation in some real being. (This conception requires the idea that there are degrees of being.) Two kinds of entia rationis are distinguished: those with a foundation in reality and those without one. The objects of logic, which include genera and species, e.g., animal and human, respectively, are entia rationis that have a foundation in reality, but are abstracted from it. In contrast, mythic and fictional objects, such as a chimera or Pegasus, have no foundation in reality. Blindness and deafness are also sometimes called entia rationis. See also AQUINAS , SUÁRE. A.P.M.