John Locke was an English physician and philosopher whose reputation as one of the most influential thinkers of the Enlightenment earned him the distinction of being regarded as the Father of Classical Liberalism. He was a pioneer in the field of consciousness, proposing a "theory of mind" that set the stage for countless future philosophers and theorists, and helped define our current concepts of "identity" and "self". His thoughts on political philosophy influenced many of the proponents of the Age of Enlightenment in Europe as well as the American Revolutionaries, and can be seen in the United States Declaration of Independence and other significant milestone documents.

In the second part of his monumental work, Two Treatises of Government, Locke developed his ideas of "natural rights" and the "social contract" as the foundation and justification for his outline of a just and civilized society. Locke proposed that the true 'law of nature' is that all people are born equal, free and independent, and everyone has the natural right to defend their life, liberty, health and possessions. No one has the right to infringe on another person's natural rights. Because everyone is born free, it is up to each individual to judge what the law of nature requires of them and no one is obligated to obey anyone else. Although Locke believed human nature in its natural state is guided by reason and tolerance, it is also prone to selfishness, and our own perceptions of fairness and justice will inevitably conflict with others. To prevent violent conflict and war, and to protect our possessions, humans choose to establish civil societies that are able to resolve conflicts in a civil way. They do this by establishing a government with fair and just laws that address our needs for security without infringing on our natural rights to life, health, liberty and possessions. This is the concept of a 'social contract.' When governments overstep this delicate balance and grossly infringe on our basic rights, we have the natural right to revolt and establish a new government that respects our natural rights.