I think it's more valid than an argument from definition. At its most cynical, a legal system is at least an attempt to disguise brute power as reason. So even

I think it's more valid than an argument from definition. At its most cynical, a legal system is at least an attempt to disguise brute power as reason. So even then there's an allowance that reason and fairness should have precedence over brute power - they just try to dress it up. So if that concept of reason and fairness being important didn't exist, they would just do away with the song and dance.