The ability of a individual to adapt to and function in a given environment = dynamic concept
"Health is the state that the body is in after having reactively adapted, while preserving its essence. Health is a physical and mental state relatively free of discomfort and suffering that allows the individual to function as efficiently and as long as possible in the community. Health is a state that allows the person who benefits from it to be fully devoted to his or her projects and capable of putting non-genetic sociocultural forces into play."
R. Dubos.
happiness and autonomy (health as perceived by the subject) = "secular" concept