Quantum mechanics allows for events to occur spontaneously without any physical cause.

We live in a world of cause and effect. Drop an apple, and it falls. But shrink down to the subatomic quantum world, and this rule breaks. Particles pop into existence out of nothing. They do it randomly and spontaneously. Scientists suggest the Big Bang itself might have been a massive, causeless quantum fluctuation. It did not need a giant finger to push the button. The rules of physics allowed it to just happen.