Outside of Reason
Space and time flows in a similar fashion as to a river.
The river starts at a small source, and as the volume of water increased, flowing from heights to lows, it splits for one reason or another. At the same time, two split rivers might reunite once more.
By repeating the cycle, the river spreads through the earth and moistens it.
Space and time are similar to that. At one point there was only one universe, but as time passed, it split into multiple universes. By flipping a coin, the universe could split simply by the outcome. If that coin was used to pick what team starts off in a football game, it could then possess the ability to largely influence said game. That split would then create a parallel universe. At the same time, it's possible for those split universes to rejoin. If that tossed coin had landed into a wishing well, the outcome wouldn't matter. The result would be buried by countless other coins and lose its meaning as it vanished into the quantum theory of probability. It is common for a universe to converge after a minute chance such as that, just like with a river. Even if a large rock blocked the flow, the river would just split up and reunite shortly thereafter. As the universe splits and reunites, history is knitted together. And we live in one of the strings of that knitted history.