What does the stock phrase "unto itself" mean?

Question

I've looked through several online dictionaries to discover the meaning of the parent phrase "unto itself". But alas, all my efforts at discovering the original definition of the preceding idiomatic phrase are to no avail, as no online dictionary provides me with an adequate explanation. I have been successful in searching for the meanings of its derivatives/variations.

Take Collins Dictionary, for example:

A law unto yourself: "If you say that someone is a law unto himself or herself, you mean that they behave in an independent way, ignoring laws, rules, or conventional ways of doing things".

Unto: "If you say that something is, for example, a world unto itself or a place unto itself, you mean that it has special qualities that it does not share with other, similar things, and so it should be treated or understood differently from those other things".

Other variations include a world unto itself, an island unto itself, a means unto itself, an entity unto itself, a world wholly unto itself, sufficient unto itself***

As I've stated in the introduction, I've been unsuccessful in my bid to discover the one true underlying definition for this elusive idiomatic phrase. Whatever definition I do search for is relegated to only its derivatives; this I find most unsatisfactory in passing my semantic muster.

Answer 1

The orginal idiom comes from the bible (Rom 2:14):

For when the Gentiles which have not the Law, do by nature the things contained in the Law: these having not the Law, are a Law unto themselves.

The original meaning was that they did the things that the law would tell them to do, despite not being subject to the law.

But the modern meaning of the idiom is the opposite. If you say "He is a law unto himself" it means he does whatever he feels like. He breaks the law freely. It also has the sense of being unconventional, different from the norm.

All other uses are secondary, and generally are just emulating the form of the idiom and not its meaning. The variations generally just mean "Isolated from others", and perhaps therefore "free of restraints that you may find elsewhere"

So I'd expect "An island unto itself" to be an isolated island. It is "unconventional" and not like other islands. If I go there I can be free of society's rules.

Likewise, I can find "Antarctica is a world unto itself": It is different from elsewhere. It is separate from the rest of the world. It has its own rules.

"a means unto itself" is not familiar to me. I can find two examples (so I don't know if that makes it an idiom):

"I no longer saw the canvas as a place of representation, but as more of a means unto itself for creating the work.

Here the writer is saying that the canvas has an independent artistic value, separate from its practical purpose of being a smooth flat sheet to hold paint.

Does protesting ever become a means unto itself?

The person is asking if "protesting" is ever done for the sake of protesting, and separate from any goal that the protest might be against.