Smith was a deist, based on the fact that Smith's writings never explicitly invoke God as an explanation of the harmonies of the natural or the human worlds. According to Coase, though Smith does sometimes refer to the "Great Architect of the Universe", later scholars such as Jacob Viner have "very much exaggerated the extent to which Adam Smith was committed to a belief in a personal God", a belief for which Coase finds little evidence in passages such as the one in the Wealth of Nations in which Smith writes that the curiosity of mankind about the "great phenomena of nature", such as "the generation, the life, growth, and dissolution of plants and animals", has led men to "enquire into their causes", and that "superstition first attempted to satisfy this curiosity, by referring all those wonderful appearances to the immediate agency of the gods. Philosophy afterwards endeavoured to account for them, from more familiar causes, or from such as mankind were better acquainted with than the agency of the gods". Some authors argue that Smith's social and economic philosophy is inherently theological and that his entire model of social order is logically dependent on the notion of God's action in nature. Brendan Long argues that Smith was a theist, whereas according to professor Gavin Kennedy, Smith was "in some sense" a Christian. Smith was also a close friend of David Hume, who, despite debate about his religious views in modern scholarship, was commonly characterised in his own time as an atheist. The publication in 1777 of Smith's letter to William Strahan, in which he described Hume's courage in the face of death in spite of his irreligiosity, attracted considerable controversy. Published works The Theory of Moral Sentiments In 1759, Smith published his first work, The Theory of Moral Sentiments, sold by co-publishers Andrew Millar of London and Alexander Kincaid of Edinburgh. Smith continued making extensive revisions to the book until his death. Although The Wealth of Nations is widely regarded as Smith's most influential work, Smith himself is believed to have considered The Theory of Moral Sentiments to be a superior work. In the work, Smith critically examines the moral thinking of his time, and suggests that conscience arises from dynamic and interactive social relationships through which people seek "mutual sympathy of sentiments." His goal in writing the work was to explain the source of mankind's ability to form