What does U(1) symmetry in gauge theory arise from?

It's turtles all the way down.

Not from bribes and/or moving faster than the regulators. Altman's projects, on the other hand...

At some point the answer is “because that’s what reality is.”

If by "reality" you mean "the universe", then the way the universe is depends on a cause, as the existence of the universe is not explained by the universe itself (even an "eternal" universe). Its existence is contingent on some other cause that ultimately cannot be contingent and thus does not require explanation.

So the cause or dare I say reason for the universe being the way it is will depend on its cause.

I feel like the language of this argument is self-undermining. The existence of the universe being dependent on a cause that is itself not contingent on anything else… As easily the existence of the universe could be not contingent with anything else.

> As easily the existence of the universe could be not contingent with anything else.

But the universe is contingent. It isn't necessary. It is one big chain of dependence.

The universe just is that way because it is. THAT is the root cause.

And you have an implied axiomatic assertion that everything must have a cause, even though that necessarily results in an infinite recursion of cause-finding.

Nowhere did I say or imply everything needs a cause. That's your baggage. In fact, it is the exact opposite: that because an infinite regress is incoherent and impossible, there must be some necessary uncaused cause where the buck stops.

"The universe" cannot be that cause, as the universe and everything in it is contingent.

In science, it is the same thing.