In this book I have argued that sociology originated in eighteenth-century philosophy, political economy and cultural history. Eighteenth-century social theory embraced both a voluntaristic pole — Vico for example — as well as a deterministic, systemic perspective — Montesquieu. The tension between these two approaches to the study of human society dominated the subsequent development of sociological positivism and Marxism. It needs emphasising that although Vico, Montesquieu, Ferguson and Millar laid the foundations for sociological theory their work was not sociology: the complex socio-historical relation between action and structure remained untheorised. Ferguson's concept of the unintended consequences of human action was never integrated with the notion of society as a system: it was Hegelian philosophy which transposed Ferguson's voluntaristic element into an organic part of totality. Later Marx developed these negative and contradictory notions into the dichotomy of the capitalist system, structured in objective laws of change, and class agency, structured in collective consciousness and political organisation. Marx's contemporaries, Comte and Spencer, equally conceived society as an organic whole, its structure determined by specific laws of evolution, but the action element was ultimately subordinated to the system and the whole.