In my dissertation, I address the problem of articulating a theory of individual moral responsibility for harms to which individual actions only marginally contribute. I argue that the difficulty of theorizing responsibility for structural harms such homelessness, global warming, or state-sponsored genocide reflects an assumption that agency is tantamount to an experience of efficacious action. In the bureaucratic societies in which we currently live, the ability to see the effects of one's actions reflected in the world can no longer signify our presence as agents in this world. Through a critical engagement with Hannah Arendt's writings on thinking and conscience, I redefine agency as an individual's ability to transform his experience of time and space from one in which these structures obscure his individual presence in the world to one in which he is a unique origin of their meaning. In thinking, the individual orients himself in the "present" of time and in a private "home" of space such that he is visible to himself and to others as a singular and unique source of action and meaning in the world. I subsequently take this notion of agency to reconceptualize moral responsibility as the acknowledgement on the part of the individual that, whatever the outcome of his actions, he remains a visible origin of his actions. This notion of agency provides us with a conceptual vocabulary with which to articulate the nature of individual responsibility for large scale events that individuals did not uniquely or significantly cause, but which could not exist in the absence of their actions and complicity. And, as a result, it more accurately captures the experience of agency in the modern world than its traditional consequentialist counterpart.