Dumb animals and plants are devoid of the life of reason whereby to set themselves in motion
 Thomas Aquinas, Summa Theologica (1274). copy citation

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Author Thomas Aquinas
Source Summa Theologica
Topic reason life
Date 1274
Language English
Reference
Note Translated by Fathers of the English Dominican Province
Weblink http://www.gutenberg.org/cache/epub/18755/pg18755-images.html

Context

“According to the Divine ordinance the life of animals and plants is preserved not for themselves but for man. Hence, as Augustine says (De Civ. Dei i, 20) , "by a most just ordinance of the Creator, both their life and their death are subject to our use." Reply Obj. 2: Dumb animals and plants are devoid of the life of reason whereby to set themselves in motion; they are moved, as it were by another, by a kind of natural impulse, a sign of which is that they are naturally enslaved and accommodated to the uses of others. Reply Obj. 3: He that kills another's ox, sins, not through killing the ox, but through injuring another man in his property.” source