On atheism, there are not actually various possible futures. That is to say, there is actually only one future that is ever possible.
Because there is no free will.
Instead, for every action, there is only an equal and opposite reaction. If a rock gets hit by another rock and falls, that’s an equal and opposite reaction, and the rock that first fell did so because of a tree root that made it break free, which itself was caused by…it’s an infinite regression of reactions to actions, all of which are exactly equal. The same thing happens for a solider who saves people on the battlefield, or when a man proposes to a woman. Free “will” is the same realm as “spirit,” which on atheism 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. It was written by Pierre-Simon Laplace in 1814. According to this determinism, if someone (the demon) knew 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 natural laws. This is true even for you, because you’re simply a large bag of atoms. Adding atoms to more atoms does not make them somehow have a spirit or “will,” so free will does not exist.
And so there is only one future on atheism. You become a serial murderer? Reaction to an action. Save a life? Reaction to an action. You’re a very complex bag of atoms, but you have the same freedom of choice as a rock: none. Your atoms are not really any different than any others, after all, and we know that will and spirit are mere superstitions. (At least if we are committed atheists.)
So there are effectively two possible belief systems:
“Given the state of the universe at one time, a complete set of laws fully determines both the future and the past. It seems we are no more than biological machines and that free will is just an illusion.”—Stephen Hawking
“For God gave us a spirit not of fear but of power and love and self-control.” —Paul of Tarsus
I think that belief in free will, however, is properly basic. I see it in my life every day, and I know that my future is very bright, even after I die. Sadly, the horror for many modern men is this: because they are nothing when they die, they are nothing. Because there is no force of will, there is no ultimate significance to their lives.