On the basis of the description developed by nineteenth-century scholars, existentialist thinkers accepted the view that humanism was a philosophy, thus clearing the way for their opponents to lay the foundations of p.a. These detractors came principally from the ranks of structuralism and conservative Marxism. Of course, Nietzsche had already developed certain premises that were later used by Levi-Strauss and Foucault. Heidegger’s critique of humanism is also a manifestation of p.a. Within Marxism, Althusser promoted the theory that there was not one Marx but two: the young, still “ideological” Marx, and the mature, truly “scientific” Marx. The conclusions that the French philosopher drew from this dichotomy include: Any thought that appeals to Marx for any kind of restoration of a theoretical anthropology or humanism is no more than ashes, theoretically. But in practice, it could pile up a monument of pre-Marxist ideology that would weigh down on real history and threaten to lead it into blind alleys. When (eventually) a Marxist policy of humanist ideology, that is, a political attitude to humanism, is achieved – a policy that may be either a rejection or a critique, or a use, or a support, or a development, or a humanist renewal of contemporary forms of ideology in the ethic-political domain – this policy will only have been possible on the absolute condition that it is based on Marxist philosophy, and a precondition for this is theoretical anti-humanism. P.A. customarily formulates its criticism of Humanism on the basis of a rigid scientism. N.H. accepts numerous criticisms of traditional Humanism, but favors the revision, not only of the prevailing idea of human being (*), that is proper to the nineteenth century, but also of the conception of science (*) that [likewise] corresponds to that era.