   As already noted, different views on how to apply the Best Interests standard roughly correspond to different theories of  well-being.   However, theories of well-being are normally developed with an ordinary fully-capacitated human being in mind, so, when applied to those whose incompetence is due, in part, to substantial deviations from this paradigm, some theories need to be adjusted to accommodate human beings who do not at the time, or ever, possess the paradigm capacities these theories presume (for example, the capacity to experience the pleasures of the intellect, or the capacity to desire). The understanding of well-being and the specifics of applying the Best Interests standard in such cases must be tailored to the details of each particular real-life condition — and to the corresponding levels of mental functioning.  Interests of children, including infants, have received some attention in the literature (Buchanan and Brock 1990, ch.5, Schapiro 1999); similar tailor-made analyses are needed for individual mental illnesses and brain deficits.