That's a really neat way of defining it, and not one I'd really thought about. (I haven't ever had to think about it, after all; it's all in the invisible knapsack.)

More generally, I think any time something is defined by what it isn't (particularly when it's presented as either a binary choice or the only slightly less oversimplified one-dimensional spectrum), there's an inherent subordination to the "real" concept.

Hooray for Russ, and Daly, and you (and your new knife).