Sometimes concessions just aren’t possible, as this snippet from Luther makes pretty clear- especially the last sentence:
On the last day of January Luther discussed many things with the licentiate of Magdeburg about the casual haughtiness of the Italians. “Although they have been convicted by the very plain Word of God,” said Luther, “it’s intolerable to them to be reformed by the Germans.
I’ve often thought to myself, ‘What if you went to the council after all in order to establish some sort of harmony?’ But no means to this end can be found, for if the pope were willing to acknowledge manifest articles of faith and his gross and palpable errors and were willing to submit to the council, he would lose his authority because he boasts that he’s the head of the church and that all its members owe him obedience. Accordingly the Council of Constance is accused of arrogating to itself authority over the pope.
If the papists made a concession to us in the most insignificant point, everything else would be put into question. Everybody would cry out, ‘Hasn’t it been said that the pope is the head of the church and can’t err?’ This is the foundation and chief claim of the papacy.
Sylvester Prierias, the master of the sacred palace, tried to frighten me with such a thunderbolt when he said, ‘Whoever questions a word or act of the Roman church is a heretic.’ At that time I was still weak. I didn’t want to attack the church. I had respect for such arguments. Now, however, I write about the council and offer the emperor this advice: that he give the Roman pontiff the liberty and power to decide and decree whatever he pleases. This is the best way to solve the problem. Little as the pope can concede anything, so little can I relax what is demanded by the Word of God.”
Sometimes, conceding something is really conceding everything. And that, well, that’s just not possible nor practical.