On atheism, there are not actually various possible futures. That is to say, there is actually only one future.
Why? Because there is no free will.
Instead, there is only equal and opposite reaction. Free “will” is the realm of “spirit,” which doesn’t exist. It’s an illusion, at least in a world without God, and atheists have long known that.
In the history of science, “Laplace’s Demon” was the first published articulation of causal or scientific determinism, penned by Pierre-Simon Laplace in 1814. According to this determinism, if someone (the Demon) knows the precise location and momentum of every atom in the universe, their past and future values for any given time are entailed; they can be calculated from the laws of classical mechanics.
And so there is only one future. You become a serial murderer? Reaction to an action and nothing more. Save a life? You had no choice. Rape five women? Well, your atoms made you do it.
Welcome to the life of being a bag of atoms. Be careful around Clippy.