One ancient theory  was an idea called vitalism, which claimed  that living things were unique because they were filled  with a special substance, or energy, that was the essence of life.
یک نظریه باستانی به نام "حیات گرایی" ادعا میکند که موجودات زنده بی نظیر هستند چون آکنده از مواد یا انرژی خاصی بوده که جوهر و ماهیت زندگی است.