Reasonable Discussions need some Common Ground

I have often been struck by how difficult it can be to have reasonable discussions on the subjects of torture, rule of law, freedom of speech, hate literature, or pre-emptive war. A reasonable discussion is based on finding some common ground, as Obama has often said. But sometimes you are so far apart that you cannot find any common ground, and the discussion falters.

Now here is an example of a discussion that has good intentions on each side (already a rare occurrence), but absolutely no common ground. Say a modern day liberal were transported back to a time before the Magna Carta, to King Arthur's Camelot. Then let's suppose you have an interesting discussion with King Arthur about "Trial by Ordeal".

You could point out to the King that torturing people to confess was not a good method of separating the guilty from the innocent. He might politely ask you what alternative there might be. You could suggest the novel idea of collecting evidence, naming witnesses, appointing a jury, getting lawyers to argue the case, all run by a judge.

He would answer "Well, according to our laws, if we have two witnesses we can convict without the confession. But we can never find two witnesses, so we always torture the accused to see if they will confess. It's much easier."

You may argue back that in the case of torture, it only depended on the accused's resistance to pain, not on their guilt. "But," says King Arthur, "The innocent man's resolve under torture will be strengthened by their innocence, and the guilty will be weakened by their poor conscience. We have never wrongly punished a person who was tortured to obtain a confession."

"But" you answer, "You have no statistics to back up your assertion. How would you know if your punishment was right or wrong? By collecting evidence you can build a scientific case against the accused without a confession. For example, footprints, objects left behind, finding stolen items in the accused's house, establishing an alibi at the time of the crime."

"Well" says the King "I do not understand the science that you speak of. And following footprints and searching the accused's house might work for a simple theft, but our most common crime is the casting of spells and black magic. Casting of spells can only be proven by confession because spells are supernatural."

There is no common ground.