 Larry Wright (1973, 1976) also offers an explanatory account targeted on the presence of the trait, but he criticizes the prior accounts for failing to capture the apparent goal-directedness of functional traits. His so-called “etiological” analysis holds that the function of X is Z means (a) X is there because it does Z, and (b) Z is a consequence (or result) of X’s being there. Because of the intended breadth of Wright’s analysis, it has been attacked on conceptual grounds (e.g., Boorse 1976), but the general thrust of the etiological account survives in accounts of function based on natural selection, discussed in section 4. 