Fitzgerald creates a very interesting dynamic regarding the certainty in Gatsby's past. On one hand, the facts about Gatsby's past are understood and make clear sense. He came from North Dakota, was born as James Gatz, and emerges from a modest background. While specific facts about Gatsby's past like these are certain, Fitzgerald suggests that individuals are not bound inextricably to this condition. In this light, the ability to redefine and reconfigure one's identity from the past is where there is a level of uncertainty about his previous incarnation. The only certainty that is extracted is that the power of one's subjectivity can make anything uncertain:
The truth was that Jay Gatsby of West Egg, Long Island, sprang from his Platonic conception of himself. He was a son of God — a phrase which, if it means anything, means just that — and he must be about His Father’s business, the service of a vast, vulgar, and meretricious beauty. So he invented just the sort of Jay Gatsby that a seventeen-year-old boy would be likely to invent, and to this conception he was faithful to the end.
Facts are understood about Gatsby's past. However, Fitzgerald suggests that what is certain is that these do not define Gatsby. He is able to "invent" his own notion of identity. This becomes the fundamental certainty that emerges about Gatsby's past. In this light, identity is not external as much as it is a subjective construction, a revelation that emerges from the "Platonic conception" that one has about themselves. Certainty is established about the elements of one's past. Uncertainty emerges as to how much these facts play into defining our own identity, and the amount of sway they carry over who we are and what we wish to be. Gatsby demonstrates this dynamic in his own life and in the way he carries himself in his relationship with his past.