A question that has concerned me for some time now is this - we say that we know what it is for something to be just, because it possesses the Form Of Justice, of truth that it possesses the Form Of Truth, just as we judge something to be an Oak Tree from having its own particular form. My concern relates to the possibility of knowing whether or not we have correctly grasped, say, Justice. This is particularly contentious, because many people today are keen to insist that there really is no such thing as Justice, or objective moral Truth (of course, these desires are connected in any case, since for something to be an injustice it would have to offend against said objective moral Truth). My question is this - yes, we say that an act (murder, say) is unjust, but in what way can we be sure that our grasp of Justice is correct in this case? In what way are we sure that murder is contrary to justice, and not merely an expression of our feelings about the matter? I do not of course believe such tosh, but I do not myself know the proper answer to this question.


 I am particularly interested in this question because I am independently debating the possibility of the existence of objective moral truth with somebody who will admit the existence of objective mathematical truth, but no other.

Thank you,
Kantus