- A contradiction between facts and theory points to a problem, but it remains unanswered from the experiment whether the problem falls in the theory, in an unquestioned fundamental assumption, or in an assumed condition particular to the case under study.#
- In Euclidean geometry we know a priori of experience that the sum of the internal angles of a triangle is equal to 180 degrees. However, this result does not hold in non-Euclidean geometries. . . . Still, one does not announce a refutation of Euclidean geometry if a measurement of the internal angles of a triangle does not equal 180 degrees. . . . The introduction of assumed real world conditions does not affect the aprioristic character of economics just like the assumption of the type of surface does not change the aprioristic character of geometry.#
- Since Austrians and non-Austrians work under different paradigms constructed over a different set of non-observable fundamental assumptions, the debate between Austrian economics and non-Austrian economics is not, or should not be, an empirical one, but a foundational one. The underlying question is which economic geometry – the Austrian, the non-Austrian, or a third one – is a more plausible reflection of the real world.#
- Because a paradigm is built on unquestioned fundamental assumptions, some of which may not be observable, and [because] a paradigmatic shift is the result of a persuasion exercise and not the result of efficient empirical tests, nothing guarantees that a change in paradigm is a step forward; it may just as well mean a step back.#

- Mill does not propose to put the
*assumptions*of economic theory to empirical tests, but only the*predicted results that are deduced from them*. And this, I submit, is what all the proponents of pure, exact, or aprioristic economic theory had in mind, however provocative their contentions sounded.#

- It is not a deficiency of the system of aprioristic science that it does not convey to us full cognition of reality. Its concepts and theorems are mental tools opening the approach to a complete grasp of reality; they are, to be sure, not in themselves the totality of factual knowledge about all things.#