Looking back at my own existence, I see a strange convergence of random factors that are highly unlikely to occur. From the Big Bang to right before my birth, a slight atomic deviation would have resulted in my nonexistence. On an individual level, the probability of your consciousness and mine existing is practically zero.
However, when looking from a broader perspective, I realize that the existence of each person is an inevitable mathematical consequence.
First, I want to assume that the multiverse exists, meaning our universe is not the only one. There are infinite universes beyond this one, which may possess parameters and physical laws that are different from or identical to ours. I think this way because I believe in mathematics and probability. There is only one way for nothing to exist, and only one way for just a single thing to exist, but there are infinite ways for infinite things to exist. Probabilistically, an infinite number of universes and realities is the most logical conclusion.
Multiverse
In such a system of infinite space and time, every event with a probability greater than zero, no matter how small, is bound to repeat. The chance of atoms arranging into you is extremely low, but it is greater than zero. When placing a probability greater than zero into the infinite set of trials of the multiverse, it does not just happen once, but will repeat infinitely.
Countless solar systems, Earths, and infinite versions of you will be born. Despite the spatial separation within the multiverse, these entities will exist in identical environments, under identical physical laws, and produce neural responses identical to yours right now.
Even though the existence of the structure called you is inevitable on a multiverse scale, your consciousness is singular and finite. There will be no reincarnation or transmigration to other versions after you die in this universe. Even if a copied version is composed of the exact same particles and carries the exact same memories as you, the spacetime coordinates of both are completely independent. Consciousness is a localized phenomenon emerging from a physical neural network. When the physical brain in this universe decays, your own stream of awareness here is entirely eradicated, permanently separated from the versions continuing to operate in other dimensions.