Second, he questions the conventional wisdom that has evolved around affirmative action. He claims that there is nothing beyond assertions and anecdotes to prove that diversity enhances the college experience for all students; that there is no systematic evidence that black "role models" are essential to the education of black students; that a "critical mass" of black students in the academic setting might actually be detrimental to the education of black students; and finally that black studies programs are "ideological crusades" which provide sanctuary for intellectual lightweights. It is this last point which makes up the bulk of his discussion on how affirmative action has led to a mismatch between minority students and the institutions they attend, setting them up either for failure or turning them out to be bad doctors and lawyers. Sowell asserts that colleges and universities which pledge to "develop minds and skills that serve society at large cannot be subordinated to the impossible task of equalizing probabilities of academic success for people born and raised in circumstances which have handicapped their development, even if for reasons that are not their fault and are beyond their control" (p. 153).