life principle
Noun
Meaning
a hypothetical force to which the functions and qualities peculiar to living things are sometimes ascribed
Source: WordNetSynonyms
Hypernyms
Hyponyms
Examples
We see in man three elements; the material body, the life principle and the element of human personality. The last has only slowly reached its present complexity and is still far from the power and perfection that we can imagine it will some day possess.