In this paper we call attention to a particular aspect of Alberto Guerreiro Ramos' sociology, which is his permanent preoccupation with the human condition in modern times. In this sense, we identify two different moments in his work: in the first, strongly influenced by the ideas of Christian intellectuals, the author drive its attention to the human nature category. In the second he shows great independence from Christian influences and creates the expression "parenthetic man", which constitutes the basis of his new theory of organizations. Such a characteristic of Guerreiro's thought allows us to affirm that his sociology is an anthropocentric one, which means that human being turns to be the main reference regarding social planning and theoretical speculations.