Matheson and Kline contend that the observational-theoretical dichotomy is motivated by a faulty assumption. What is it?

That science is in the business of discovering theoretical entities.
That we can know about features or properties of observable objects with certainty.
That our technical prowess will continue to allow us to view smaller and smaller items.
That comparing theories is important.
That causation works at the micro scale in the same fashion as on the macro scale.