Solipsism

"What do we know about him?" "Not much, professor. He was covered in dirt and sand, the uniform he was wearing was very weathered. Nothing in his pockets except for ammunition, explosives, and maps. There was a radio too but we can't get it to connect on any channel." "Insignia?" "Just one thing, over his left breast pocket on the uniform. It reads 'U.S. Army'."