When Locke advises that rulers cannot always and in every situation govern in accordance with a standing law, his point is not the prudence of having an emergency powers act on the books or to debate the merits of the Roman dictatura. It is rather to justify to men — specifically, those who would have supported Parliament’s cause against the Stuart kings in the name of law — a power which in its nature is hostile to every attempt at legal regulation. Prerogative is extra-constitutionalism in defense of the public good. Its being extraconstitutional means that no institution possesses the legal authority to compel a prince to cease exercising prerogative or to judge its use in a manner that all must accept. Abuses of prerogative are redressed in revolutions, not law courts or legislative chambers (2nd Tr., §168). Prerogative is beyond the reach of every law.2
That is, Locke pitches prerogative to an audience disinclined to accept it. His purpose is to overcome that resistance. He justifies the sweeping scope of prerogative by reference to the inability of legislators to provide for the community’s well-being. It is thus an exception to the rule that the society must be governed by settled, standing laws: prerogative is not the norm.3 It is a sometimes-superior means of achieving the same end as pursued by law, viz. the public good.
Yet this is only one of the law’s ends. The other is to be a check on government abuses, to prevent the community’s power from being turned against it. Government by stated rules of right not only clarifies the duties of the subject but also hinders the rulers from pursuing their own interests under the shadow of the public good (i.e., from abusing the trust of prerogative, cf. 2nd Tr., §§87–8, 124–6, 134–7, 210). Prerogative certainly doesn’t advance this goal by other means. Locke must therefore persuade his sympathetic readers that the ideal of lawful government must be abandoned from time to time.
The anti-tyrannical aspirations of the rule of law call to mind an ideal of automatic execution: the ruler should look to the case at hand, consult the legal code, and then do whatever it commands. The executive would in essence simply follow an algorithm. Law would take the form of a series of situation-action pairs.4 The rights and duties among subjects, it seems, are just the reflection of commands to officers and magistrates concerning whom to punish, whom to grant restitution. This is very much like Hans Kelsen’s description of law, except that Locke permits less discretion under the rubric of “law.”5 If the situation at hand were not covered by the code, or the code demanded an absurd response, then the prince should instead exercise prerogative.6
And here we come to Locke’s argument for why prerogative is necessary, why it is not simply endemic to an immature legislative code. Such an exhaustive string of prescriptions, covering every possibility and never harming the community or committing an injustice, would require an unimaginable degree of foresight. General guidelines will not cut it, given the ends of law: on the contrary, permitting the police to employ the sort of balancing tests so popular in jurisprudence would be to grant them precisely that discretion which the laws must restrict. Every law is consequently limited by the imaginativeness of its legislator. Justice is easy; predicting how it is to be applied in every case is hard. The exceptional situation is what dooms the exorcism of extralegal action.
“Things of this World are in so constant a Flux, that nothing remains long in the same State” (2nd Tr., §157). Legislators are not “able to foresee, and provide, by Laws, for all, that may be useful to the Community” (2nd Tr., §159). It is “impossible” to “foresee, and so by laws to provide for, all Accidents and Necessities, that may concern the publick” (2nd Tr., §160). The ability to be “so much Masters of future Events” as to legislate well for every occasion is beyond human capacity (2nd Tr., §156).
The emphasis on prescience in these statements might suggest that the problem is largely epistemological. And indeed a reading of the Essay Concerning Human Understanding supports this impression. We cannot have certain knowledge concerning causes and effects in the natural world, and so it is always possible that something surprising will arise.7 Of course, the probability that our understanding of the basic laws of physics is wrong in any catastrophic way is relatively low, and an extralegal power that finds its justification in our inability to predict earthquakes or asteroid impacts is of only a marginal interest to politics.
What is more undetermined, and thus most in need of an extemporaneous response, is the result of human interactions. We might say that it is not so much the dearth of physics as of economics and political science that is problematic. This dearth takes on what might seem to be comically absurd proportions. Locke’s weighty judgment, stated in such a way as to signal that a profound thinker is revealing an important truth, viz. that the fundamental character of worldly things is a constant flux, that Heraclitus was right and Parmenides wrong, that there is no cosmos, only chaos, no being save what our minds fix in ideas and that these minds, too, are becoming — this abyss before which men seek succor in the Lord, is made manifest in the fact that Old Sarum sends two members to Parliament, even though nobody lives there anymore (cf. 2nd Tr., §157).8 An analogous situation surrounds the prince’s exercise of the federative power: it cannot be regulated by antecedent laws because, being “done in reference to Foreigners,” it depends “much upon their actions, and the variation of designs and interests” (2nd Tr., §147). Just as Machiavelli’s Fortuna is seen more in the sacking of Rome by the Gauls than in evils which come from heaven, so too is Locke’s flux more a matter of human freedom than of natural disasters.9
For John Dunn, prerogative revealed the depth of Locke’s piety; Filmer’s stable world, by contrast, rested on his “naïvely providentialist assumptions.”10 Instead, Locke argued that men make their social world, and so are responsible for it — they cannot blame God or expect Him to resolve their difficulties. “God made Human Nature, the potentialities inherent in the species, the framework within which human life takes place. But men make human history.”11 This means accepting that there are real difficulties to which there may be no complete resolution. Prerogative, the inability to legislate difficulties away, is the acceptance of this truth. Pasquale Pasquino gives the same account, except with History instead of God.12 And Harvey Mansfield sees in this flux the resonances of Machiavelli’s fortuna, necessita, and accidenti.13 The same story can be told with or without God, as the moral is that God will not resolve our political problems and that the fundamental fact about politics is disorder.14 That is, what appears to be a cosmological statement about the flux of all things in fact reveals an anthropological or political truth.
All of this might appear to flow from Locke’s uncompromisingly narrow conception of law. It must be conceded that his ‘jurisprudential theory’ would not pass muster in contemporary philosophy of law discourse. H. L. A. Hart, for example, thought Kelsen’s account of law too paradoxical to describe what actually goes on in courts,15 and Locke manages to occupy a more extreme position than Kelsen! Indeed, we must even question whether Locke had a fully developed theory on the subject, as it isn’t treated at length in the Two Treatises (or anywhere else, so far as I am aware). It is certainly incompatible with the common law tradition, and perhaps even with significant portions of a civil law approach. Yet contemporary philosophy of law tends as a whole to begin with the practice of law: not everyone may take law to be whatever a court of law will enforce, but it seems that every theory must bear at least some relation to actual legal practice if it is to be taken seriously. This is not at all Locke’s procedure. He instead asks what is required from the government for society to adequately safeguard its members’ lives, liberties, and estates, and has the answers to this give law its definition. Locke is less constrained by the accidents which shaped his society’s legal order than a legal theorist. He would be undeterred by Hart’s criticism.
To recapitulate, the constant flux of worldly things which justifies the rulers’ departures from the law might have a purely epistemic source. Regardless of the underlying reality, the limitations on what can be known entail that the world must always appear as flux to the human (and consequently, the political) understanding. Yet a little bit of examination reveals this to be formally true but largely irrelevant. It is, rather, human beings whose unpredictability is at issue. The “Things of this World” that are “in so constant a Flux” are human things. The world in which man lives is not an orderly one because his main concern is social, not natural or divine: it is man as he relates to other men, not as he relates to gods and acorns. The implications of this are treated as if indubitable.