Some physicists assert that quantum mechanics violates this cause/effect principle and can produce something from nothing, but this is not so.
Theories that the universe is a quantum fluctuation must presuppose that there was something to fluctuate—their ‘quantum vacuum’ is a lot of matter-antimatter potential—not ‘nothing’.
Also, if there is no cause, there is no explanation why this particular universe appeared at a particular time, nor why it was a universe and not, say, a banana or a cat which appeared.
This universe can’t have any properties to explain its preferential coming into existence, because it would not have had any properties until it actually came into existence." W.L. Craig
