I'm interested in the issue of whether people would have moral responsibility under determinism. So if a person in a deterministic universe would happen to commit murder, some people would say that they are morally responsible for the action, and others would disagree. When I speak of "moral responsibility" here I'm thinking along the lines of whether the person would deserve blame and retributive punishment.
(If it actually happened that we lived in a deterministic universe, I assume that we would have to hold people morally responsible in some sense for practical reasons. We would have to punish to protect society and to deter future crime; but some might give up on the idea of retributive punishment and see criminals rather as unfortunate victims of the blind process of nature.)
I'm not expecting a solution to the question, "Would people be morally responsible under determinism?".
Rather I'm going to ask: could the issue be a conflict of opposing moral principles that may just be forever unsolvable by rational argument? So maybe you just can't produce arguments that can "bridge the gap" between the two sides, i.e. The arguments just don't exist that would have the rational force and traction against the other side.
Do some moral disputes, like this one, come down ultimately to people holding differing instinctive moral principles that can't be proved or disproved?