I gave an example of something that almost everyone agrees exists but is very hard to define or quantify. Anyone can play the game you are playing here. How do you know your measuring device really exists? Your point is without merit.
How do you know your measuring device really exists?
How can I know a calculus test exists? Very easily. I look at it, feel it, etc. How can I know calculus ability exists? Again, very easily - it predicts outcomes on a set of correlated exams, the existence of which I verify with sight, touch, etc.
You seem to want to argue that education only produces vague, immaterial and unmeasurable outcomes. Lets take that as a given - in that case, why not just eliminate education spending and save $900B/year?
Outcomes not being well defined != unnecessary or worth getting rid of.
You seem to confuse physical existence and idea. Presumably a physical object can be painted but ideas can't. Lot's of things exist that can't be verified by sight, touch, etc. In my opinion being a good teacher is not something that can be reasonably measured. I'm open to the possibility that I'm wrong but have seen no evidence that I am.
