The universe exhibits certain laws of nature, e.g. gravity, electromagnetism, and the strong and weak atomic forces. There are three ways of explaining the uniformity of nature, where the uniformity of nature entails things that happen over and over again.
1. The uniformity of nature is either the result of chance, necessity or design. (Premise)
2. Whenever something happens over and over again, it is not the result of chance. (Premise)
3. Therefore, the uniformity of nature is either the result of necessity or design. (From 1 and 2)
Atheists obviously don't want to embrace the design alternative, but (2) appears rationally compelling. Yet, I don't hear many atheists theorize that the uniformity of nature is the result of necessity. My speculation on the matter is that atheists view the existence of anything necessary as too God-like. After all, if the uniformity of nature is necessary, then we're left with Spinoza's pantheistic God, e.g. that God and Nature are identical.
I suggest that if the atheist is going to take seriously the need to explain the uniformity of nature, then he cannot possibly say it's the result of chance. Why not simply adopt pantheism instead? Not that I think there are good reasons to believe that the uniformity of nature is necessary, but I do think it's a vastly better explanation than chance.
If you were to win the lottery once, you might think you were lucky. Imagine you win the lottery a thousand times in a row. Surely you would conclude that this was not the result of chance, but you would also be reluctant to say it's the result of necessity. You didn't have to win the lottery a thousand times in a row, which leads us to the design alternative: you win the lottery a thousand times in a row because someone chose to rig the lottery results.
Even so, necessity is a much better explanation than chance. At least necessity can explain why things have predictable patterns of order and regularity.
I suggest the most viable option in explaining the uniformity of nature is design, and that necessity comes in at a distant second, but is still a much better explanation than chance.
If the uniformity of nature is by design, we might be asked the following rhetorical question: who designed the designer?
The question is misguided for at least two reasons. In order for an explanation to be best, we don't have to have an explanation of the explanation. If we did, then there would be an infinite regress of explanations, and then nothing could be explained at all. Secondly, theists do say that the designer has an explanation of his existence. As the designer of the universe, he would have to transcend the universe. Since the universe is the sum total of all physical space, time, matter and energy, the designer must be timeless, changeless (for time is a measurement of change), and immaterial, in addition to being very powerful and very intelligent.
You will recall that the Principle of Sufficient Reason (PSR) states:
PSR: Everything that exists has an explanation of its existence, either in the necessity of its own nature or in an external cause.
Therefore, the designer does have an explanation, and that explanation is found in the necessity of the designer's own nature. After all, it's impossible to cause something timeless and changeless, since causing such a thing would mean that it changes from a state of non-existence to existence, which is a contradiction. Therefore, if the objector insists that the designer must have an explanation, the theist is happy to comply, adding only that the designer's explanation is found in his own necessity.