The first principle of life in living things; the first act of a body capable of life. 

Vegetative Soul.— The soul in plant bodies that are capable of self-nourishment, growth, and reproduction. 

Sensitive Soul.— The soul in animal bodies that are capable of self-nourishment, growth, reproduction, sense perception, desire, and locomotion. 

Intellectual Soul (also called Rational Soul).— The human soul by which we are capable of self-nourishment, growth, reproduction, sense perception, sensitive desire, locomotion,  intellectual knowing, intellectual desire.  The intellectual soul is unique in that it can subsist in separation from the body that it informs.