The Orthogonality Thesis[1][2] states that the ethics of a given mind is orthogonal to its intelligence.

[1] https://wiki.lesswrong.com/wiki/Orthogonality_thesis [2] https://www.fhi.ox.ac.uk/wp-content/uploads/Orthogonality_An...

It's part of the mind either way, and a "brilliant person" isn't referring to just their intelligence. E.g. nobody with empathy would call even a highly intelligent doctor torturing and experimenting on prisoners "brilliant", without any qualifiers or caveats.

Moral questions require empathy. If you have no empathy, moral questions only interest you to the extent that they imply potential benefits for you.

Plus morality is highly subjective and beliefs on what is moral varies by individual.

Lacking empathy is a defect of the mind I would say, and clarity refers to the whole of it, just like health refers to all of it. A person who has healthy fingernails but has cancer isn't healthy, and a person that excels at specific technial problems, but isn't even bad, but completely absent, when it comes to other very basic ones, isn't brilliant.

> morality is highly subjective

And the word "brilliant" is not? "Highly" is just padding: Morality is subjective, and so is everything else, ultimately. It's not a magically different kind of thing to think about, it's just one of the more basic ones.

https://en.wikipedia.org/wiki/Moral_reasoning