Heims is a writer and teacher living in Paris. In this essay, he considers how Calderón uses the very uncertainty of perception that is central to the drama of Life Is a Dream as the force that enables the human exercise of free will.

When Rosaura appears during the first moments of Life Is a Dream, descending from the craggy mountains where her wild flying horse has left her, the audience is confronted by ambiguity and uncertainty. The unreliability of sense perception, one of the problems around which the entire play revolves, is presented in this scene. Rosaura appears to be a man; yet, when that man begins to talk, despite appearances, the man is a woman: “Unkindly, O Poland, do you receive a stranger; for you inscribe her arrival in your land with blood; and hardly does she arrive, but she comes to grief...