42. All the more fruitful elements in Spinoza's political doctrine are lacking in that of Hobbes, but the principle of the two theories is very much the same. Each begins with the supposition of an existence of human individuals, unaffected by society, and each struggling for existence against the rest, so that men are 'natura hostes.' Each conceives 'jus naturale' as = 'potentia naturalis.' But Spinoza carries out this conception much more consistently. He does not consider that the natural right, which is might, ceases to exist or becomes anything else when a multitude combine their natural rights or mights in an 'imperium.' If the ostensible 'imperium' comes into collision with the powers of individuals, single or combined, among those who have hitherto been subject to it, and proves the weaker, it _ipso facto_ ceases to be an 'imperium.' Not having superior power, it no longer has superior right to the 'subditi.' It is on this principle, as we have seen, that he deals with the question of limitations to the right of a sovereign. Its rights are limited because its powers are so. Exercised in certain ways and directions they defeat themselves. Thus as he puts it in _Epist_. L. (where he points out his difference from Hobbes), 'Supremo magistratui in qualibet urbe non plus in subditos juris, quam juxta mensuram potestatis, qua subditum superat, competere statuo.' Hobbes, on the other hand, supposes his sovereign power to have an absolute right to the submission of all its subjects, singly or collectively, irrespectively of the question of its actual power against them. This right he considers it to derive from a covenant by which individuals, weary of the state of war, have agreed to devolve their 'personae,' in the language of Roman law, upon some individual or collection of individuals, which is henceforward to represent them, and to be considered as acting with, their combined powers. This covenant being in the nature of the case irrevocable, the sovereign derives from it an indefeasible right to direct the actions of all members of the society over which it is sovereign.