The distinction between "negative" and "positive" freedom focuses on the political and ethical subject's relationships with herself and with other people. Materialists have tended to focus more on the direct contribution of the social circumstances in which the subject finds herself (e.g. her relationship to the means of production and the means of subsistence). In this talk I try out one strategy for reconciling the former focus with the latter, one rooted in the political ideal of self-determination, which I associate with the latter group of thought. I'll attempt to describe subjective security as a resource that allows a person to extend herself across time, institutions, and persons in ways that are vital for securing her freedom, and sketch some political implications of this view.