This dissertation has as its object Sor Juana Inés de la Cruz (1648 or 1651-1695), nun and poetess who lived in New Spain. Among others subjects, she wrote about knowledge apprehension by human beings and defended that women could access formal education, like men. The main goal in studying her was to situate her writings within her time, explaining the context in which she lived and identifying the place that she occupied in XVII century colonial world among literate and religious women. To that, Sartrean concept of projection was adopted to guide the questions for the documents, i. e., the analysis were made by looking the projections Sor Juana had for her future. In addition, another general presupposition was to understand her as a child of her own time, and not to ignore the historicity of her life. Two main results were reached: the first one is an hypothesis about the reason that led Sor Juana to choose Father António Vieira as her opponent in "fineza" documents; the second one is an interpretation about her concept of "negative benefits", considering that her theological formulations had as motivators her personal project of studying.