or professional discipline. He worked as a civil engineer during the railway boom of the late 1830s, while also devoting much of his time to writing for provincial journals that were nonconformist in their religion and radical in their politics. Writing Spencer published his first book, Social Statics (1851), whilst working as sub-editor on the free-trade journal The Economist from 1848 to 1853. He predicted that humanity would eventually become completely adapted to the requirements of living in society with the consequential withering away of the state. Its publisher, John Chapman, introduced Spencer to his salon which was attended by many of the leading radical and progressive thinkers of the capital, including John Stuart Mill, Harriet Martineau, George Henry Lewes and Mary Ann Evans (George Eliot), with whom he was briefly romantically linked. Spencer himself introduced the biologist Thomas Henry Huxley, who would later win fame as 'Darwin's Bulldog' and who remained Spencer's lifelong friend. However, it was the friendship of Evans and Lewes that acquainted him with John Stuart Mill's A System of Logic and with Auguste Comte's positivism and which set him on the road to his life's work. He strongly disagreed with Comte. Spencer's second book, Principles of Psychology, published in 1855, explored a physiological basis for psychology, and was the fruit of his friendship with Evans and Lewes. The book was founded on the fundamental assumption that the human mind was subject to natural laws and that these could be discovered within the framework of general biology. This permitted the adoption of a developmental perspective not merely in terms of the individual (as in traditional psychology), but also of the species and the race. Through this paradigm, Spencer aimed to reconcile the associationist psychology of Mill's Logic, the notion that human mind was constructed from atomic sensations held together by the laws of the association of ideas, with the apparently more 'scientific' theory of phrenology, which located specific mental functions in specific parts of the brain. Spencer argued that both these theories were partial accounts of the truth: repeated associations of ideas were embodied in the formation of specific strands of brain tissue, and these could be passed from one generation to the next by means of the Lamarckian mechanism of use-inheritance. The Psychology, he believed, would do for the human mind what Isaac Newton had done for matter. However, the book was not initially successful