Thomas Hobbes (5 April 1588 - 4 December 1679), was an English philosopher, considered to be one of the founders of modern political philosophy. Hobbes is best known for his 1651 book Leviathan, in which he expounds an influential formulation of social contract theory. In addition to political philosophy, Hobbes contributed to a diverse array of other fields, including history, jurisprudence, geometry, the physics of gases, theology, and ethics, as well as philosophy in general. John Locke (29 August 1632 - 28 October 1704) was an English philosopher and physician, widely regarded as one of the most influential of Enlightenment thinkers and commonly known as the "Father of Liberalism." Considered one of the first of the British empiricists, following the tradition of Sir Francis Bacon, Locke is equally important to social contract theory. His work greatly affected the development of epistemology and political philosophy. His writings influenced Voltaire and Jean-Jacques Rousseau, many Scottish Enlightenment thinkers, as well as the American Revolutionaries. His contributions to classical republicanism and liberal theory are reflected in the United States Declaration of Independence. John Locke (29 August 1632 - 28 October 1704) was an English philosopher and physician, widely regarded as one of the most influential of Enlightenment thinkers and commonly known as the Father of Liberalism. Considered one of the first of the British empiricists, following the tradition of Sir Francis Bacon, Locke is equally important to social contract theory. His work greatly affected the development of epistemology and political philosophy. His writings influenced Voltaire and Jean-Jacques Rousseau, many Scottish Enlightenment thinkers, as well as the American Revolutionaries. His contributions to classical republicanism and liberal theory are reflected in the United States Declaration of Independence.