Three commonly mentioned philosophical precepts of occupational therapy are that occupation is necessary for health, that its theories are based on holism and that its central components are people, their occupations (activities), and the environments in which those activities take place. However, there have been some dissenting voices. Mocellin, in particular, advocated abandoning the notion of health through occupation as he proclaimed it obsolete in the modern world. As well, he questioned the appropriateness of advocating holism when practice rarely supports it. Some values formulated by the American Occupational Therapy Association have been critiqued as being therapist-centric and do not reflect the modern reality of multicultural practice.