To navigate such unquantifiable hazards, then, you need to make judgment calls. And that's where argument (or discussion, or conversation, if you prefer) comes in. You want diverse, even opposing viewpoints. You want to manage their interactions in a way that allows the quieter, less-senior, less-predictable voices to be heard. You probably do want to accord different weights to the arguments of different people, although deciding how to do so (past track record? clarity of argument?) is hard.