Adam Smith
The Scottish philosopher who explained why some countries get rich, and who is quoted most confidently by people who have not read him.
The Wealth of Nations appeared in 1776, the same year as the American Declaration of Independence, and asked a question nobody had answered properly: why are some countries rich and others poor? Adam Smith's answer was that wealth comes from productivity, productivity comes from dividing work into specialized tasks, and how far you can divide the work depends on how big your market is. Almost everything else in the book, including a long attack on empire, follows from that.
Smith was a professor of moral philosophy at Glasgow. Economics was not yet a profession. His first book, The Theory of Moral Sentiments in 1759, argued that people judge themselves by imagining how a neutral observer would see them, and that our ability to feel what other people feel is the basis of morality. He never took it back; he was still revising it in the last year of his life. The idea that Smith described human beings as pure self-interested calculators comes from reading one of his books and not the other.
What the book actually says
The famous pin factory opens the argument. One worker making pins alone might produce a handful a day. Ten workers splitting the job into eighteen separate operations produce tens of thousands. So anything that widens the market, roads, canals, safe shipping, free trade, makes a country richer.
The phrase everyone knows, the invisible hand, appears exactly once in the whole of the Wealth of Nations, in a passage about why merchants prefer to invest at home. Later generations promoted a small observation into a slogan. Smith's actual argument is narrower: the butcher and the baker supply your dinner out of self-interest rather than kindness, and a system that lets people follow their own interests will usually allocate effort better than ministers directing it from above.
He is also consistently suspicious of businessmen. He writes that people of the same trade seldom meet without the conversation ending in a conspiracy against the public, that the interests of merchants often run against the interests of everyone else, and that any commercial regulation those merchants propose should be examined with great suspicion. He wanted public schooling for the poor, taxes in proportion to what people could afford, and public works, and he worried that repetitive factory work would make workers stupid unless the state educated them.
Empire as a bad investment
The most political part of the book is the attack on mercantilism, the idea that a country grows rich by running trade surpluses and piling up gold. Smith argued that a nation's wealth is what it produces and consumes, not the metal in its treasury, and that colonies and monopoly trading companies enrich a small group at everyone else's expense. He looked at the British Empire in America and concluded that the taxpayer paid for it and the merchants collected from it. In 1776 he proposed either giving the colonies representation in Parliament or letting them go.
He allowed one exception. Defense, he wrote, is of much more importance than opulence, and on those grounds he accepted the Navigation Acts that protected British shipping. That sentence is the ancestor of every modern argument for protecting a strategic industry.
Smith spent his last years as a commissioner of customs in Edinburgh, collecting the tariffs he had criticized for a career, and by all accounts liked the work. He had his unpublished manuscripts burned before he died in 1790. Both sides of today's trade argument quote him, and both are quoting the same book.