Hobbes, one of the most famous of all political philosophers, is most famous for his work 'Leviathan', which deals with how society came about in the first place, and what the duties of the members of society are to it. Society in Hobbes' sense means centralized government, leadership, and laws. Hobbes' is so famous partly because of the quality of his work, and partly because he was one of the very first political philosophers who did not rely on religion to found his system, and so is often considered to be one of the founding fathers of modern political philosophy. (Machiavelli similarly did not base his ideas on religion, and in fact predated Hobbes, but he did not establish a system in the same way as Hobbes did, and so is usually held in less esteem.)

Hobbes' crucial first argument is that before society existed, there was what he dubs the 'state of nature'. He held that this lawless state was a time of everyone for themselves. If someone wanted what his neighbor had, he would simply take it, and probably kill the neighbor in the process. Hobbes had a very bleak view of humanity, and famously declared that life in the state of nature would be nasty, brutish and short. According to Hobbes, there is no absolute good or evil, no innate moral code which regulates people's behavior (a popular idea during his time - most fully and influentially explicated in the writings of Aquinas); there are only lusts and desires. In the state of nature people would do whatever was necessary to satisfy these desires, unfettered by any considerations of conscience. Since the resources of the world are finite, people would have to fight to get what they wanted, to take it away from others.

As time proceeded the state of nature would get progressively worse, as the desire for revenge for old crimes would perpetuate violence, and feuds would develop. And as the population grew, so would people have to fight more often as resources became scarcer. Further, since, according to Hobbes, everyone lusts after power, each would seek to gain dominance over others, or if they couldn't gain dominance would in their envy at least try to lay others low, and thus elevate themselves in relation to their rival. Hobbes held, rightly I believe, that no person is so much more powerful than others that he/she has nothing to fear from anyone else. Even the strongest must sleep, and even the weakest can band together with others and overcome the strongest. Thus no one would have security; everyone would be in constant fear for their lives.

The state of nature therefore ends up being a state of total warfare between all peoples, where no one is safe. Hume, writing later than Hobbes, seemed to basically agree with Hobbes on this point, and added the excellent point that under such a state there can be no science or art; in short, nothing that takes time to produce and doesn't contribute directly to survival. For why spend a lot of time on something secondary to survival when it could be stolen from you at any moment?

Hobbes claimed that eventually people would use their reason, and decide that this state of nature was intolerable. They would seek peace and security, and the only way to do this is to submit to a higher authority. The people would agree to forfeit their ability to pursue others for crimes and to do whatever they wanted, in exchange for a centralized protection. This is the basic concept of the Social Contract, one of the major positions in the political philosophy (Hume, Rousseau, and Locke are some other famous proponents of a social contract idea). A government, the Leviathan of the title, is set up, and a ruler is chosen and has access to armed forces (to make the Leviathan stronger than any of their subjects). People agree to abide by the rulings of the Leviathan, and lose the ability to do what they want to others. This loss is acceptable to them because all others must do the same, and therefore what they already own (and their own person and family) is secured from the avarice of others.

Obviously the common objection to this is that having laws is one thing, getting people to obey them is quite another. Hobbes' answer was that in order to get the system to work, the Leviathan must make the punishments for crimes, and the chances of getting caught, so steep that no reasonable person would take the chance of committing a crime. If the punishment for murder and theft is execution, and the chances of getting caught are very high, then clearly very few people are going to attack their neighbor simply to gain a bit more property, or out of an old grudge.

As you might guess from the above, Hobbes' Leviathan was not a democratic form of government. Once the Leviathan was installed, Hobbes argued that the only way to maintain peace was for the subject to submit absolutely to the Leviathan. They maintained only the right of nature - that is, the right to self-preservation. After all, the purpose of the Leviathan is to protect its subjects, therefore if the Leviathan is not doing this then it has broken its end of the contract; therefore the subject need not uphold their end of the contract i.e. obeying the Leviathan. However, the Leviathan was not required to submit to this right. For example, Hobbes said that if a draft was instituted then a person had the right to refuse to join up on the grounds of self-preservation; however the Leviathan could have the person executed for refusing! People under a Hobbesian Leviathan had no rights as we would understand them. They had to do what the Leviathan said without question as long as the Leviathan wasn't ordering them to do something injurious to themselves, and Leviathan had no limits to its power. Hobbes considered that this was best for the majority of people; it was preferable that a few get destroyed by the Leviathan, rather than everyone descending into the state of total warfare that preceded the Leviathan.

Hobbes thought that separation of church from state was a good idea to avoid strife (remember his Leviathan's primary purpose is to maintain peace at any cost), but argued that any separation of powers or checks and balances, was contradictory to the purpose of the Leviathan. In his system there would be no legislative branch or judiciary, just one absolute, supremely powerful executive (although the executive didn't have to be one person, it could be small group of people). Only through one leading body having absolute power, could all conflicts be avoided.

Objections

Objections are obvious and numerous. Clearly the easiest line of assault is to argue that the state of nature would not be as bad as Hobbes' claimed: in other words not bad enough to justify such a totalitarian form of government. Alternatively one could argue that such a loss of liberty is an even greater evil than the loss of security in the state of nature. In addition there is the question of international war, clashes between Leviathans which might cause the deaths of multitudes of their subjects. In the state of nature, since there are no organized armies, such huge wars would be impossible.