The idea of possible worlds was posited by Leibniz as a way of explaining the existence of evil. He insisted that the actual world is the "best of all possible worlds," a claim famously mocked in Voltaire's Candide. Modal logic uses the idea of possible worlds to evaluate the necessity, possibility, contingency, or impossibility of propositions. Many physicists theorize the actual existence of these possible worlds: the cosmological notion of the multiverse postulates that there are in fact other universes where other versions of our own selves are waiting, dying, laughing, eating in slightly different or exactly similar ways. An interpretation of quantum theory allows for a similar possibility, that all possible pasts, presents, and futures are in fact real.
The ontological possibilities quickly slip into existential realities: it is not some other person on the screen that is doing this particular thing at this particular minute. It is not only a possible world, it is a possible Self: I am waiting, I am laughing, I am eating, I am dying. These images that pass before me on at the screen are negatives of my own soul, a life that I have lived, will live, am living, eternally (enter Nietzsche's eternal return). Surrounded by this possible "now", we are thrown back onto our own now, and there are moments of anxiety during the film, not only the images of anxiousness, suffering, and death, but the constant reminder with each frame that time has passed, that I am here now, that the future is not yet. “The Clock” turns the gaze back onto the gazer, and we cannot help but “watch” our own lives, and the anxiety we may feel is not only at the truth of the “object” nature of our lives that unavoidably ends in death, but the “subject” nature that reminds us that the future is open, that we are “condemned to be free.”