Man alone we believe to have a subsistent soul: whereas the souls of animals are not subsistent.
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic soul animal
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/17611/pg17611-images.html

Context

“Further, the soul of brute animals moves the body. But the body is not a mover, but is moved. Therefore the soul of brute animals has an operation apart from the body. On the contrary, Is what is written in the book De Eccl. Dogm. xvi, xvii: "Man alone we believe to have a subsistent soul: whereas the souls of animals are not subsistent." I answer that, The ancient philosophers made no distinction between sense and intellect, and referred both to a corporeal principle, as has been said (A. 1) . Plato, however, drew a distinction between intellect and sense;” source