I'm just going to say this. Just because the value of so.ething is unknown, doesn't invalidate it's properties. 1,2,3,4,X. X HAS A VALUE. To disregard it because you don't know it's value is leaving something on the table that can very well be useful. Before we had absolute values for things, we had relative comparisons. These comparisons are what became engineered values once there was a way to assign numbers to them. Before "engineering" we knew that bronze was in some ways better than wood, and iron was better than bronze. There were no numbers then; just experience.