What is existence relative to time? A man who seems to be obsessed with the past, Antoine Roquentin shifts through multiple periods of time. Once eager to give life to the dead Marquis de Rollebon, he slowly loses his interest in recreating the past and becomes overwhelmed with nausea. Life seems to be a field of flowers filled with colors and life. But is there more to life than what meets the eye? When we see a rose, the first thing that catches our eye is the beauty that is outlined by the vivid colors of the petals. What we see next is the vivid color of the stem, followed by the pointy thorn. We see the thorn last because it is something our minds tend to look past, as it is only natural to look past the poison and find only the pure. What we get when we begin to analyze past the beauty and research the true skeleton of being, is exactly what Roquentin received once he realized the truth of his existence. Nausea.
Like Roquentin, the past seems to be an important time for Anna as well. "I live in the past." (page 152) But what connection does the past have with the present, relative to existence? It is not possible to understand the meaning or the basis of existence without first living through the experiences (or, in other words, the veil of lies that blinds a man from the truth) that cause your existence to have a particular essense. All creatures develop within a case, and none are born with the nausea of truth. Once they emerge from the case, they see the world for the first time, and the last thing on their mind is why they exist. Following their birth, they develop memories, and deal with the many "lies" of life that create their essence. And therefore causes them to forget what they truly are, and it is that exists within them. "The function explained nothing: it allowed you to understand generally that it was a root..." (page 129) It is once the essence is destroyed or moved aside that men realize the truth, that it is possible to define one's own essence. Therefore, in order for a being to define an essense, a being must first define its own existence; but this cannot be done without fluctuating between the past and the present. Realizing what defines a person's essence becomes the key to defining his existence, and in doing so, allows them to redefine their own essence.
