Well, in this contrived scenario, you can't tell what would happen if the driver _didn't_ push down on the gas pedal while going up the hill. The relationship between the gas pedal and the speed of the car is entirely obscured.
However, in a real world system, the chance that there is zero imbalance is also nearly infinitesimal. You could take the most skilled driver in the world and you would still be able to pull out the relationship between gas pedal and speed out of his driving pattern. Similarly, with the right variables and enough data, you could pull a relationship like the one described here out of economic data.
(As a side note, I think the way in which this article is written is pretty obnoxious. The first 500 words are dedicated to the author congratulating himself for being aware of an idea that he hasn't even explained yet.)
However, in a real world system, the chance that there is zero imbalance is also nearly infinitesimal. You could take the most skilled driver in the world and you would still be able to pull out the relationship between gas pedal and speed out of his driving pattern. Similarly, with the right variables and enough data, you could pull a relationship like the one described here out of economic data.
(As a side note, I think the way in which this article is written is pretty obnoxious. The first 500 words are dedicated to the author congratulating himself for being aware of an idea that he hasn't even explained yet.)