Laffer curve D. Rockefeller and Henry Ford. While he served as Secretary of the U.S. Treasury Department his wealth peaked at around US$300–US$400 million. Personal income-tax receipts rose from US$719 million in 1921 to over US$1 billion in 1929, an average increase of 4.2% per year over an 8-year period, which supporters attribute to the rate cut. David Hume also expressed similar arguments in his essay "Of Taxes" in 1756, as did fellow Scottish economist Adam Smith, twenty years later. The Democratic party made a similar argument in the 1880s when high revenue from import tariffs raised during the Civil War (1861–1865)
To each according to his contribution is derived from greater training requirements, job intensity, safety hazards, etc.—the more one is rewarded for the labor contributed. The purpose of the principle, as Trotsky would later state, is to promote productivity. This is done by creating incentives to work harder, longer, and more productively. The principle is ultimately a stowaway from capitalism that, according to Marx, will vanish as work becomes more automated and enjoyable, and goods become available in abundance. The principle has its roots in the way that capitalism manages its affairs. That is, each is rewarded according to how much he produces. Remuneration increases as