What's the meaning of the phrase "we are not above" in what follows? What exactly does this phrase mean in this sentence? [duplicate]

We are above something if were are too moral to do it:

He was above denying his colleagues' share in the credit.

If we are too wealthy to deem to do it:

He was above worrying about where his next meal will come from.

Or if it will make us look bad, or we are of too high a social standing:

I am above getting into petty scraps in public.

In contrast therefore, we are not above something if we are not too moral to do it:

Jeffrey Archer is not above sleeping with prostitutes, bribing them, and then perjuring himself in false libel actions.

If we don't care about something making us look bad:

Jeffrey Archer is not above claiming to be the youngest ever MP even though someone seven years younger was already sitting in the very same parliament.

Or if we have the money to avoid doing something odious:

Jeffrey Archer is not above writing trashy novels that treat the English language worse than he does prostitutes, journalists, and the truth.

Generally, when we are above doing something, it means that we don't do it because we are "better" than the sort of person who would, for some value of "better" (wealth, morality, wisdom, privilege, social standing, esteem, self-esteem). When we are not above doing something, it means that we do do it, because we are "worse" than the the sort of person who wouldn't, likewise by various different criteria.

In most cases, to say someone is above something means that they didn't do it, and we approve their not doing it, while to say that they aren't above it means that they did it and we disapprove. So, in my examples about Jeffrey Archer, I'm saying that I disapprove of his behaviour in each case. (Since you'd mentioned him, and I needed examples of odious behaviour, they came quickly to mind).

Pause before I move onto the exception. Don't read the next bit until you're happy you understand the previous...

Okay, the exception is when the "better/worse" relates to privilege. Here we if we say that a rich man "isn't above working with his hands" or a boss "isn't above helping out on the floor when it's busy" we mean that they aren't using their privilege to shirk such work, and we probably approve of that.

We might also use this "above" idiom in a sarcastic way, so saying "oh, he's above talking to the likes of us" could mean "he thinks he's better than us, but really he isn't". But this is a sarcastic use of irony, so it's a deliberate inversion of the normal meaning.

In the example given, the speaker doesn't approve of the fact that William Kane talked to the lawyer whether because he thinks it sneaky, thinks it bad form that he is engaging a lawyer outside of the family firm, thinks it bad form to enquire so closely after finances (an attitude among very "old money") or some other reason (or no sane reason whatsoever and it was just badly written).

In English, we say that we are above something, or something is beneath us, when it is something we want distance ourselves from, metaphorically speaking.

The metaphor of relative height is an ancient one, not limited to the English language. Higher things are better than lower things. In some cultures, to show the bottom of your shoe to someone is a grave insult. It puts you beneath them.

So I might say I am above thieving, meaning that I am better than a thief.

In another circumstance, I might say I am not above thieving, meaning that I am willing to be a thief.

above: too honorable to yield or succumb

It's helpful to understand a meaning of the word

beneath: lower than, as in rank or station, unworthy of, unbefitting

Update

So, in your example

"...he is not above going to an independent lawyer to find out his legal position."

Therefore, the sense of the statement is that he is not so honorable that he would not employ an independent lawyer.

(This may be somewhat sarcastic, because today, it is often considered wise to obtain an independent opinion, especially where money and health are involved.)

According to this source,

he is not above going to an independent lawyer to find out his legal position

simply means that

he doesn't mind seeing a lawyer to find out his legal position
Or
he doesn't think he should not consult a lawyer to find out his legal position.