In A General Theory of Authority, Yves Simon writes that “The power in charge of unifying common action through rules binding for all is what everyone calls authority.” Immediately after this statement, Simon drops a footnote discussing various relations between the concept of authority and the concept of law. Here is that footnote in its entirety:

Between the concept of authority and that of law there exist enlightening relations. It is, indeed, perfectly proper to speak of the authority of the legislator, and nothing would warrant the identification of authority with executive power. Many acts of authority assume the form of laws passed by assemblies. However, authority and law evidence opposite intelligible tendencies inasmuch as the more a proposition is expressive of necessity, the more it participates—other things being equal—in the character of law, where there is nothing in the concept of authority that expresses aversion to contingency. A law rules human acts in the capacity of premise, not of conclusion; now, the more a premise is independent of contingency, the more of a premise it is. The first or absolute premises regulating human actions express the absolute necessities intelligibly following upon the rational nature. But authority is perfectly at home in the management of contingency and in uttering of practical conclusions. A decree which applies a law to a particular and unique situation is no less an act of authority than a law passed by an assembly to establish a principle that can be applied to indefinitely many particular situations. No doubt, this law is already so particularized, and so engaged in contingency as not to be a sheer expression of natural necessity. Yet it retains the character of premise, and calls for further determination in terms of adjustment to contingencies that an assembly cannot deal with. Common usage contrasts “government by law” and “authoritarian government.” Both of these expressions are objectionable, and their meaning has to be carefully specified. In a way every government is authoritarian. On the other hand, “government by law” conveys the suggestion that propositions retaining the character of premises may suffice to guide a community in entirely concrete and perhaps unique situations, and this involves the nonsense of a premise which is also an ultimate conclusion. Provided these abusive interpretations are definitely ruled out, it is perfectly correct to use the expression “government by law” when a political system depends as much as possible on premises established by the wisdom of the legislator, and to call “authoritarian” the system of government which gives the few men in the executive power the greatest possible liberty to manage the concrete circumstances by connecting the conclusions of their choice with premises that have no other source than their good judgment, since no positive enactment ever gave these premises any juridical existence. (A General Theory of Authority, pp. 48-49 n.11.)