Both of your statements are straw men. If you're proceeding purely from history, it's not supportive to say that armies on opposite sides of the world fight ea

Both of your statements are straw men. If you're proceeding purely from history, it's not supportive to say that armies on opposite sides of the world fight each other more rarely than armies next to each other. A more apt test of my assertion would be the frequency with which civil wars (excluding cross-ethnic wars in poly-ethnic societies) are initiated vs non-civil wars (allowing for the variance caused by internal policing, international politics, etc). Just because Poles and Germans are similar to you doesn't mean they're similar to each other. On the latter, I'd prefer a more fair: ISIS and a non-ISIS armed force are engaged in a firefight. An alien ship crash lands and disembarks five non-humanoid aliens. These aliens immediately begin shooting at both parties. What happens?