John Locke (1632-1704) was a British philosopher whose innovative ideas on the purpose and regulation of government has given him the title of spiritual father of the U.S. Declaration of Independence and our Constitution. John Locke is also recognized as the founder of British Empiricism which hypothesized that innate ideas about the world do not exist. The only knowledge we can obtain is through sensory perception and experience.
During Locke's lifetime England played witness to many revolutionary thoughts on the function and role of government. The English Civil War (1641-1651) between the monarchy and the Parliament resulted in the execution of the King of England Charles I in 1649 and the establishment of a commonwealth (sans monarch). Eventually Charles II, son of Charles I, was restored to the throne in 1660, but his son (James II) was later overthrown in the Glorious Revolution of 1688. This resulted in the establishment of a constitutional monarchy with Parliament gaining significant power. In the following two years (1689 and 1690) Locke wrote his treatise "Concerning Civil Government".
John Locke wanted to understand why we needed government and how it could be useful. He thought that the purpose of government is to protect individual rights and property. Property is what we accumulate through our labors and no one should be able to take that away from us (not even the government). Our rights include life, liberty and the freedom to rebel against unjust governments. While this did justify the revolutions in England, it also supported the American revolution a century later.
Locke also had the novel idea that government should have its authority separated into different branches and be regulated between these units by checks and balances. The executive branch would have judicial responsibilities and the other division was made of Parliament, which had the authority to remove (impeach) the executive. This is very similar to our government, except of course that the judicial branch is separate from the executive (depending on who you ask).
Locke's ideas had an enormous influence on our founding fathers and it is fascinating to see the progenitor of our own constitution.
As Thomas Jefferson wrote, "Bacon, Locke and Newton, I consider them as the three greatest men that have ever lived, without any exception".