Women should marry when they are about eighteen years of age, and men at seven and thirty; then they are in the prime of life, and the decline in the powers of both will coincide.
AristotleWhat has soul in it differs from what has not, in that the former displays life. Now this word has more than one sense, and provided any one alone of these is found in a thing we say that thing is living. Living, that is, may mean thinking or perception or local movement and rest, or movement in the sense of nutrition, decay and growth. Hence we think of plants also as living, for they are observed to possess in themselves an originative power through which they increase or decrease in all spatial directions.
Aristotle