Indulging ourselves in the brute determinations of who I am

 This, the existentialists argue, is because such properties are never mere  Indulging ourselves in the brute determinations of who I am but are always in question. 

Who I am depends on what I make of my “properties”; they matter to me in a way that is impossible for merely available and occurrent entities. As Heidegger puts it, existence is “care” (Sorge): to exist is not simply to be, but to be an issue for oneself. In Sartre’s terms, while other entities exist “in themselves” (en soi) and “are what they are,” human reality is also “for itself” (pour soi) and thus is not exhausted by any of its determinations. 

It is what it is not and is not what it is