 Affirmation of such a state, argued de Lubac, overlooked the decisive difference between the created human spirit and other natures.Moreover, while allowing Catholic theologians to defend the essential integrity of fallen human nature against the Protestantism that denied it, the system effected a separation between nature and the supernatural that would prove pernicious - by rendering the latter (seemingly) superfluous.Although, de Lubac argues, the system of 'pure nature' was perceived to be a novelty when it first developed, it eventually came to be taken for granted, such that, by the twentieth century, rejecting it became synonymous with denying the gratuity of the supernatural.