Hobbes starts with the most basic ideas about human beings, focusing on human thoughts, which he describes as representations or appearances of real objects. These representations arise when an external object presses upon one of the human senses, triggering nerve signals that send messages to the brain. The brain then processes these messages as sensations sight, sound, smell, taste, and touch.

Of Sense and Imagination

Until Judgment Day, no single religious authority holds universal power over Christians only God and individual rulers have authority. Because sovereignty cannot be divided, Hobbes rejects the idea that one Christian leader, such as the Pope in Rome, can claim power over Christians in other commonwealths. This would diminish the authority of local rulers and weaken the stability of their governments. He argues that true salvation does not require submission to any earthly religious authority but instead depends on sincere faith in Christ.

A sovereign has the right to punish subjects who disobey the law, and the fear of punishment must outweigh any perceived benefit of breaking it. The destruction of a commonwealth often results from a ruler’s willingness to accept a diminished authority.People may deny their ruler’s power out of ignorance or for personal gain, but the consequence is always the same: the weakening of sovereignty undermines the very purpose of a commonwealth. Thus, people must respect their sovereign as long as doing so does not violate divine law or the laws of nature.

Of the Rights of Sovereigns and the Limits of Obedience

To escape this chaos, people are drawn toward certain agreements, which Hobbes calls the laws of nature. These laws, given by God, state that every person has the right to protect their life by any means necessary. However, they also emphasize the pursuit of peace whenever possible.The only way to ensure peace is for individuals to give up their right to self-preservation through violence and transfer that right to someone else via a contract. The laws of nature dictate that promises must be kept unless both parties agree to dissolve them.

Since objects are always in motion, constantly exerting pressure on our senses, humans experience a continuous stream of thoughts and impressions. However, Hobbes distinguishes between the object itself and the image it creates in the mind.Hobbes contrasts his view with that of Aristotle, who argued that vision and hearing are caused by "visible" and "audible species" that depend on the appearance of an object rather than the object itself. According to Hobbes, when a person stops perceiving an object, an image of it remains in their mind, which he calls imagination.

The apostles instructed their followers to obey human rulers in all matters, even if those laws conflicted with God's law. In the end, God expects people to follow their earthly sovereign until Christ returns, at which point the saved will enter into a new covenant as Christ’s subjects. Hobbes concludes Leviathan by arguing that the misinterpretation of scripture fueled by Aristotle’s flawed philosophy and the Catholic Church’s desire for political authority has plunged the commonwealth into a "kingdom of darkness." His book, therefore, seeks to reveal these errors and correct them.

A sovereign may appoint officials to help govern the commonwealth, but no officer can ever hold more power than the sovereign. Any attempt to divide or weaken the sovereign’s power threatens to return society to the state of nature, where war is inevitable. As long as the commonwealth remains intact, subjects must obey their ruler. If the sovereign is captured in war and voluntarily surrenders power, the people must follow the new ruler. However, if the sovereign resists and refuses to relinquish power, the subjects remain bound to their original ruler.

Hobbes identifies three types of commonwealths: monarchies, aristocracies, and democracies.In a monarchy, sovereign power rests with one person; in an aristocracy, it is held by a small group; and in a democracy, it belongs to the people as a whole.Since a commonwealth can only take one of these three forms, Hobbes argues that the strength of a government depends on its structure, rather than the number of people within it. Each form of government has advantages and disadvantages, but Hobbes believes monarchy is the best.

Of the Different Forms of Commonwealth

Hobbes also criticizes the misconception that God’s kingdom is identical to the Christian church. Instead, he argues that God’s kingdom exists wherever there is a contract between God and his people, such as the covenant between God and the Israelites. God made agreements with Adam in the Garden of Eden and later with Moses, making the Israelites God’s chosen people. However, since these covenants no longer exist in their original form, God's kingdom cannot be fully realized until Christ’s second coming, when he will establish his rule on earth or in heaven through a new contract.

Life in the state of nature is nasty, brutish, and short

In the state of nature, all people are equal. However, when two individuals desire the same thing, they become enemies, seeking to destroy one another. Since nature lacks a mechanism for resolving disputes, people exist in a state of constant conflict, where they must fight for survival and respect. Without a central authority, life is marked by continual warfare.

Of the Natural Condition of Mankind

Thomas Hobbes begins Leviathan by arguing that human life is nothing more than the mechanical movement of arms and legs, just as any machine with artificial life functions. He extends this idea to human creations, including art and governance, describing the state also known as the commonwealth or the great Leviathan as an "artificial man."

The Artificial Man

Over time, these images fade, turning into memory, and having multiple memories of different things leads to experience. Since imagination, memory, and experience are all rooted in human sensory perception, no thought or concept can ever be infinite. While Hobbes acknowledges that God's power is infinite, he argues that this only means it cannot be fully understood by humans.

To solve this problem, people create commonwealths, forming a society under a unified power. This arrangement is based on a contract where individuals surrender their right to self-preservation to a single person or group, known as the sovereign. The purpose of a commonwealth is to protect its people from harm and ensure their happiness. The sovereign wields absolute power, which cannot be taken away or divided. A ruler cannot be accused of wrongdoing by their subjects, nor can they be punished for any perceived injustices. The sovereign alone determines what is necessary to maintain peace.

Of the Causes, Generation, and Definition of a Commonwealth

To understand Hobbes’s argument fully, he explains the biblical concepts of "body" and "spirit." In scripture, these are referred to as corporeal and incorporeal substances. A body occupies space and has mass, while a spirit, like a ghost, is intangible. According to Hobbes, calling something “incorporeal” contradicts common meanings, as nothing can be both incorporeal and have a body. When the Bible refers to "the spirit of God" being present in the air or in people, Hobbes interprets this metaphorically as faith, rather than as a literal part of God’s body inhabiting another being.

Of the Kingdom of God and the Kingdom of Darkness

People learn about divine laws through natural reason (a gift from God), revelation, or miracles. In a Christian commonwealth, individuals believe in God’s spiritual authority, but this does not require them to abandon reason and common sense. Christian commonwealths depend on sacred texts that outline moral and civil laws, and in some societies, these religious rules are incorporated into the legal system. Despite uncertainties about the authorship of holy scripture, these texts are regarded as God's word and hold significant influence over Christian communities.

Full summary of Leviathan by Thomas Hobbes

Thomas Hobbes' Leviathan, from 1651, is one of the first and most influential arguments towards social contract. Written in the midst of the English Civil War, it concerns the structure of government and society and argues for strong central governance and the rule of an absolute sovereign as the way to avoid civil war and chaos.