 This was the core of the “experimental method” for Bentham; it was an approach implicitly associated in his mind with a materialist ontology and a representational theory of meaning. He rejected all forms of idealism in philosophy and insisted that in principle all matter is quantifiable in mathematical terms, and this extends to the pains and pleasures that we experience—the ultimate phenomena to which all human activity (and social concepts, such as rights and duty) could be reduced and explained.