Our hero did not believe in brandy, abstractly or concretely.
Concretely he told him that he ought to "extend his audience eastward."
He must give all, not abstractly, but concretely, synthetically.
By our enemy I do not mean anything as concretely commonplace as the German nation.
But most possibles are not bare, they are concretely grounded, or well-grounded, as we say.