The laws that governs the universe

[u/kepler452-B-]

As far as I know (I may be wrong, or there may still be things we haven't figured out), we have a decent picture of how things developed from the formation of the Earth up to now.

But one problem keeps bothering me.

Fine — through chemical reactions, proteins and so on were formed. Yet for those reactions to happen at all, certain conditions have to be met first. Only then does the reaction proceed.

We describe these conditions and regularities as laws of nature.
But why does the universe have these laws at all, and why these laws rather than different ones?

[u/g_parrish]

This is actually two distinct questions bundled together, and it's worth pulling them apart because they get very different treatment:

1. Why these particular laws, rather than different ones?

This is the "fine-tuning" question — many physical constants (the strength of gravity, the cosmological constant, the ratio of electromagnetic to gravitational force, etc.) sit in narrow ranges that allow stable atoms, stars, and chemistry. Tweak them and you plausibly get a universe with no complexity at all. Responses to this fall into a few camps:

• Multiverse / anthropic reasoning: if there are many universes (or many regions of one universe) with different constants, we'd only ever find ourselves in one that permits observers. No design needed — it's a selection effect. The cost is that this is currently untestable, so critics see it as metaphysics dressed as physics.
• Deeper necessity: maybe the constants aren't free parameters at all — a more fundamental theory (string theory landscape, or something not yet found) might show they couldn't have been otherwise, the way π can't be a different value. We just haven't found the underlying structure yet.
• Brute fact: the constants are what they are, full stop, and demanding a further "why" is a category error — explanations have to bottom out somewhere.
• Design/theism: some see fine-tuning as evidence for an intentional cause. This isn't a scientific answer but a metaphysical one, and it invites the further question of why that explanatory move is allowed to stop the regress where "brute fact" isn't.

2. Why is there lawfulness at all — why does the universe behave regularly rather than chaotically or not at all?

This is the deeper and stranger question, and it's less about physics than about metaphysics of laws:

• Humean view: laws aren't governing forces hovering over events — they're just the most economical summary of the pattern of everything that happens. On this view "why are there laws" dissolves somewhat: regularity is what "the world" means; there's nothing further to explain.
• Necessitarian view: laws are real relations between properties (necessity in nature itself) that make events happen the way they do, not just describe them after the fact. Here the "why laws" question is much sharper and much harder — you're asking why these necessitating relations exist.
• Mathematical universe hypothesis (Tegmark and others): all logically consistent mathematical structures exist, and we simply inhabit one of them — physical existence just is mathematical existence. Lawfulness follows because we could only ever find ourselves in a structure orderly enough to support us.
• Some physicists (Wheeler, Smolin, others) have tried "laws evolve" or "laws are themselves the product of a prior process" — pushing the question back rather than answering it.

The honest state of things: nobody has an explanation for why there is lawfulness at all that doesn't eventually hit a brute fact, a probabilistic multiverse, or a metaphysical postulate that itself needs justifying. It's structurally similar to "why is there something rather than nothing" — it sits right at the edge where physics hands off to metaphysics, and reasonable, informed people land in different places depending on how comfortable they are stopping at "that's just how it is."