 This critique of historicism and holism is balanced, on the positive side, by Popper’s affirmation of the ideals of individualism and market economics and his strong defence of the open society—the view that a society is equivalent to the sum of its members, that the actions of the members of society serve to fashion and to shape it, and that the social consequences of intentional actions are very often, and very largely, unintentional. This part of his social philosophy was influenced by the economist Friedrich Hayek, who worked with him at the London School of Economics and who was a life-long friend. Popper advocates what he (rather unfortunately) terms “piecemeal social engineering” as the central mechanism for social planning: in utilising this mechanism, intentional actions are directed to the achievement of one specific goal at a time, which makes it possible to determine whether adverse unintended effects of intentional actions occur, in order to correct and readjust when this proves necessary. This, of course, parallels precisely the critical testing of theories in scientific investigation. This approach to social planning (which is explicitly based upon the premise that we do not, because we cannot, know what the future will be like) encourages attempts to put right what is problematic in society—generally-acknowledged social ills—rather than attempts to impose some preconceived idea of the “good” upon society as a whole. For Popper, in a genuinely open society piecemeal social engineering goes hand-in-hand with negative utilitarianism, the attempt to minimise the amount of suffering and misery, rather than, as with positive utilitarianism, the attempt to maximise the amount of happiness. The state, he holds, should concern itself with the task of progressively formulating and implementing policies designed to deal with the social problems which actually confront it, with the goal of mitigating human misery and suffering to the greatest possible degree. The positive task of increasing social and personal happiness, by contrast, can and should be left to individual citizens, who may, of course, act collectively to that end. “My thesis”, Popper states, is that