to mechanical engineering. He contrasts his criticism of Platonic Idealism with Marx's criticism of utopianism, advocating for a piecemeal approach to learn and change our views as we act. The Background of Plato's Attack Chapter 10, titled "The Open Society and Its Enemies" like the book itself, examines Plato's belief in happiness as part of his political program and argues that Plato's treatment of happiness is "analogous to his treatment of justice", and similarly distorts general usage by tying the concept to class hierarchy. Popper believes that Plato's mission was to fight against social change and social dissension. The breakdown of the closed, tribal society, chiefly caused by the development of sea-communications and commerce, led to the partial dissolution of old ways of life, political revolutions and reactions, and the invention of critical discussion, which was free from magical obsessions. Athenian imperialism developed these two as its main characteristics. Popper discusses Thucydides' attitude towards democracy and Athens's empire, arguing that Thucydides was an anti-democrat who viewed Athens's empire as a form of tyranny. Popper defends Athens' imperial expansion by arguing that tribalist exclusiveness and self-sufficiency could only be superseded by some form of imperialism; he explains why some of the most thoughtful and gifted Athenians resisted the open society's attraction, and introduces the "Great Generation", the generation that lived in Athens just before and during the Peloponnesian War, which he considers a turning point in the history of mankind. Finally, he discusses Socrates' criticism of Athenian democracy and his belief in individualism, as well as what he considers Plato's betrayal of Socrates by implicating him in "his grandiose attempt to construct the theory of the arrested society". Plato's argument against democracy, as Popper interprets it, is based on the belief that the root of evil is "the 'Fall of Man', the breakdown of the closed society"; according to Popper, Plato "transfigured his hatred of individual initiative, and his wish to arrest all change, into a love of justice and temperance, of a heavenly state in which everybody is satisfied and happy and in which the crudity of money-grabbing is replaced by laws of generosity and friendship". Addenda A 1957 addendum to the first volume, "Plato and Geometry", discusses Popper's treatment of Plato's views on geometry. A 1961 addendum, titled "The Dating of the Theaetetus", discusses the dating of the Platonic dialogue by that name. A second 1961 addendum, titled "Reply