Is the 2nd Law of Thermodynamics invariant?

[Matt R.]

"When all systems taking part in a process are included, the entropy either remains constant or increases.... no process is possible in which the total entropy decreases, when all systems taking part in the process are included." This is a statement of the 2nd law of thermodynamics in terms of entropy from my physics textbook.

I am wondering if the 2nd law is invariant. If it is invariant, why is the universe in its current state, and not in a state of maximal disorder. In other words, why are there small "clusters" of low entropy in the universe (galaxies, planets, life forms, the human brain), when the state of maximal entropy would have clusters of matter and energy strewn randomly about.

Is the 2nd law of thermodynamics correct, or just an oversimplification (similar to Newton's laws of motion) that is only applicable to what we can experimentally observe? Is there an "easy" and well accepted solution to this question that I'm unaware of?

If you claim to "know" the answer, please state that it is a well accepted theory. If you have an opinion, feel free to state it as well (i.e. I would just like to know that it's an opinion, and not that 99% of physicists believe it to be true).