Euclid's first common notion is this: Things which are equal to the same things are equal to each other. That's a rule of mathematical reasoning and its true because it works - has done and always will do. In his book Euclid says this is self evident. You see there it is even in that 2000 year old book of mechanical law it is the self evident truth that things which are equal to the same things are equal to each other.
You think I'm ignorant of what you're up to because you haven't discussed this scheme with me as you ought to have done? When have I ever been so easily bamboozled? I believe you when you insist that amending the Constitution and abolishing slavery will end this war. And since you're sending my son into the war, woe to you if you fail to pass the amendment.