Philosophical discourse surrounding time travel traditionally engages with concepts such as the Grandfather Paradox, the possibility of time travel, issues surrounding causation, and the effects such concepts have on the nature of the metaphysics of time and change. However in this project, time travel will be assessed by its ethical consequences through contemporary pieces of popular culture, namely Christopher Nolan’s Interstellar. Philosophically, this project will engage with Jean Paul Sartre’s Being and Nothingness and his essay Existentialism is a Humanism in addition to Baron d’Holbach’s The System of Nature, as the two will be presented in direct opposition to one another as representatives of philosophies of free will and hard determinism. The objective of this project is to assess whether ethical judgements are justified or necessary in the depictions of time travel I will be referencing by evaluating whether characters are free to act responsibly or predetermined to act in ways in which they have no influence over. The object of this project will therefore be time travel, assessed through the philosophical concepts of Sartre and d’Holbach, in the context of ethics. The position this essay wishes to argue in favour for is that Sartre’s philosophy of freedom allows one to manifest one’s own moral character, and this moral character is the ultimate determinant in ethical dilemmas. There does however exist vast amounts of overlap in the two opposing philosophers’ theses however the difference lies in Sartre’s notion of bad faith which highlights d’Holbach’s refusal of his ability to choose as problematic. Therefore, the overarching argument of this project is that it is one’s own moral character that dictates their future decision making, and the formulation of such character is done through choice and freedom. Due to the philosophies of Sartre and d’Holbach hugely predating the idea of time travel, I will first give a brief description of the scientific underpinnings of the procedure of time travel, then discuss d’Holbach’s and Sartre’s philosophies, before finally applying the latter to the former.