I do not think this question can be answered adequately unless the thinker takes a 'moral realist' (moral reality) position - defined as a reality independent of the Mind.
A Thought is an "immaterial activity" in an immaterial reality.
If so, how does a thought (in an immaterial reality independent of Mind) inform the Brain (a material medium dependent on Mind).
But there is, as you probably have guessed, a deeper problem involved:
The Body-Mind Problem - or, more accurately in my view, The Body-Mind-Soul Problem
So, in addition to taking a moral realist position, the thinker must also take a position regarding either the Dualism of Body and Mind, or the Dualism of Body and Soul.
But whatever position is taken - Body/Mind or Body/Soul - my question remains : How does an immaterial activity (eg thinking a thought) inform a material medium (eg the brain).
Common-sense suggests a thought (eg of lifting the arm) informs the brain (the arm lifts). But how does it do this?