22 There are laws permitted by the Constitution which exhibit features, at least individually, that are contrary even to aspects of common, "thin" notions of the rule of law. This point can be illustrated by reference to the eight desiderata or elements in Lon Fuller's classic exposition on the rule of law**[30], an exposition adopted in large part by numerous others[31]. One aspect said to be part of this notion of the rule of law is that laws should not change too frequently. But, as Fuller accepted, this aspect "seems least suited to formalization in a constitutional restriction"[32]. Legislation is not invalid if it creates criteria subject to constant change by applying a body of general law which "picks up the case law as it stands from time to time"[33]. Another aspect of a thin notion of the rule of law, described as "one of the most essential ingredients", is that laws must be clear[34]. But this Court has held that the Constitution does not prohibit vague or unclear laws[35]. Another aspect, the absence of which Fuller described as "truly a monstrosity"[36], is that laws, and particularly criminal laws, should not be retroactive[37]. But this Court has held that there is no constitutional proscription even against retroactive criminal laws[38]. Another aspect is that laws should be general. But this Court has upheld laws that are specific to corporations, individuals, or small groups of people[39]**.