The opposition of desire and being is too simple because central to desire is desire for being. In the case of mimetic desire, when you perceive what you take to be an other's satisfaction and t ink 'why not me?' you are already leaning on a sort of cogito: you come into existence through the question of a satisfaction, a fullness experienced as elsewhere, and so of your own shameful lack of being, and your need to dissimulate this, and hence your entitlement to cut across the rules to set things right. In desire you make yourself the exception, both the place of being and the place of the loss of being.