Chapter 23, "The Sociology of Knowledge", discusses the historicist philosophies of Hegel and Marx, which attempt to predict and control change in a changing social environment. Popper argues that this attitude is closely related to "the Marxist doctrine that our opinions, including our moral and scientific opinions, are determined by class interest, and more generally by the social and historical situation of our time". Popper introduces the sociology of knowledge and argues that scientific objectivity is achieved through "the friendly-hostile co-operation of many scientists" and the public expression of criticism and opinion. He also criticizes the sociology of knowledge's failure to understand the social aspects of scientific method and suggests that the social sciences need a social technology that can be tested by piecemeal social engineering. Popper believes that social scientists should forget about intertwining 'knowledge' and 'will' and focus on the practical problems of our time using the same theoretical methods as other sciences. Chapter 24, "Oracular Philosophy and the Revolt against Reason", explores "the conflict between rationalism and irrationalism", which is "has become the most important intellectual, and perhaps even moral, issue of our time". In the sense in which he speaks of it in this chapter, rationalism is "an attitude that seeks to solve as many problems as possible by an appeal to reason, i.e. to clear thought and experience, rather than by an appeal to emotions and passions" – it is not opposed to "empiricism", but rather to irrationalism, the attitude which instead "insists that emotions and passions rather than reason are the mainsprings of human action". Popper argues for individualism and the need for rational thinking in society, while critiquing the irrationalist position that he believes is fashionable today. Popper proposes critical rationalism, "which recognizes the fact that the fundamental rationalist attitude results from an (at least tentative) act of faith—from faith in reason." This is opposed to uncritical or comprehensive rationalism, which "can be described as the attitude of the person who says 'I am not prepared to accept anything that cannot be defended by means of argument or experience'", including rationalism itself – which Popper believes is self-defeating. The choice between adopting a more or less radical form of irrationalism or critical rationalism is not just an intellectual decision but a moral one, which "will deeply affect our whole attitude towards other men, and towards the problems of social life". Popper argues that