The capacity to think critically is a form of "human capital", defined as biological plant and equipment that can be leased out to employers. Human capital is consolidated through an investment decision in acquiring a credential from an institution which provides such credentials on a fee-for-service basis. From the efficient markets hypothesis it follows that it must be the decision to so invest which is the sole determinant of the capacity for critical thinking. For it to be otherwise, there would have to exist some form of market failure, which is of course unthinkable. Therefore, merely being in a position where one is asked to demonstrate critical thinking, is sufficient enough a demonstration of it. And, as Descartes almost put it, "I think critically, therefore I am employable." [Throws mortarboard in the air.] Hooray for education!