This is the great designer argument and it is false. If particle 'a' collides with particle 'b' certain consequences follow. But, in an infinite universe, that collision is precisely a matter of chance. It is the very definition of chance. Particle 'a' may just have easily collided with particle 'c' and things would be completely different. Things are as they are, and not as one of the other infinite possibilities, because of that chance collision.