I agree; the typical human brain balks and runs away when faced with a scale of merit whose max-point is 0.

Zero does seem more appropriate either as a minimum or a midpoint. If everything is going to be negative then flip it around and say 'less is good'! But the main problem I have with only losing honor based on making predictions is that it essentially rewards never saying anything of importance that could be contradicted. That sounds a bit too much like real life for some reason. ;)

There's gotta be a way to fix this so that a perfectly calibrated person would gain a tiny amount of honor each day rather than lose it. It might not be elegant, though. Got any ideas?

The tricky part is not so much making up the equations but in determining what criteria to rate the scale against. We would inevitably be injecting something arbitrary.