Mathematics, as Galileo wrote, is the language in which God has written the universe. Whilst we may disagree as to whether there is a God that has anything to do with it, we may expect that anybody who has studied the fundamental laws of the universe will at least agree to the core of Galileo's statement, namely the proposition that natural law is essentially mathematical.
Mainstream science takes the mathematical essence of natural law for granted, rather than attempting to explain it. The nearest it comes to an explanation is the multiverse theory: a nigh on infinite number of universes have existed, but only those in which natural law is essentially mathematical are capable of producing life, so we should not be surprised to find ourselves in just such a universe. As discussed in the lemma 'There are purposes' this explanation has an Occam score of 0310, relative to QO or the Big Bang theory.
In QO, the mathematical nature of natural law is a consequence of how natural law develops. This is explored in the lemma 'Interconnectedness'. It has an Occam score of 0000, relative to QO, and is therefore to be preferred.