لا يجوز لأحد أن يكون قاضيًا في قضيته؛ لأن مصلحته ستنحاز حتمًا بحكمه، وربما تُفسد نزاهته. وبالقدر ذاته، بل بأولى منه، لا تصلح جماعة من الناس لأن تكون قاضيةً وخصمًا في آنٍ واحد.

“No man is allowed to be a judge in his own cause; because his interest would certainly bias his judgment, and, not improbably, corrupt his integrity. With equal, nay with greater reason, a body of men are unfit to be both judges and parties at the same time.”James Madison — Federalist No. 10