For example, astrophysicists now know that the values of the four fundamental forces — gravity, the electromagnetic force, and the â€œstrongâ€ and â€œweakâ€ nuclear forces — were determined less than one millionth of a second after the big bang. Alter any one value and the universe could not exist. For instance, if the ratio between the nuclear strong force and the electromagnetic force had been off by the tiniest fraction of the tiniest fraction — by even one part in 100,000,000,000,000,000 — then no stars could have ever formed at all.
Multiply that single parameter by all the other necessary conditions, and the odds against the universe existing are so heart-stoppingly astronomical that the notion that it all â€œjust happenedâ€ defies common sense. It would be like tossing a coin and having it come up heads 10 quintillion times in a row.
The entire article, which is quite short for such an important topic, is worth a read.