 Metaphysics, especially ontology, has invoked part–whole concepts ever since Aristotle founded the subject.Husserl (1970) (German original first published in 1901) was the first to consciously elaborate a part–whole theory (on which see Tieszen 1995).However he employed no symbolism or logic, even though his doctorate was in mathematics and Georg Cantor was his friend and colleague; Husserl wrote only for his fellow philosophers.