 This peculiar stance is clearly displayed in al-Farabi’s discussion of deficient cities and societies. While the details differ across his various treatises dedicated to this topic, the scale by means of which he assesses ‘excellence’ and ‘deficiency’ is consistently those two factors identified above: knowledge and action, on both the common and the class-related levels. Thus, for instance, in the Political Regime he distinguishes six deficient forms of cities, among which he lists the “necessary societies” (Political Regime C, 2, 93: 76, substituting ‘societies’ for ‘associations’). This kind of society or city, he explains,