Plants, Animals, People, Aliens: An Aristotelian-Thomist Perspective on Life in the Universe

Aristotle famously maintains in his treatise On the Soul that there are three kinds of living things-- plants, animals, and humans--and he speaks of each kind as having a soul. St. Thomas Aquinas adopts these same views. Nowadays, however, many thinkers reject them on the grounds that they are incompatible with modern science. Molecular biology is seen as affording a superior way of categorizing life forms. Evolutionary biology appears to have established that humans are simply primates wit...