Thomas Hobbes
Looking at human nature, we will see that humans are very selfish and that we are willing to hurt each other if we think it will help us. Naturally, humans are all equal because we are all strong enough to kill each other—even a child can kill a strong man while he sleeps. Imagine what things would be like without a government. It would be terrible—a "state of war". There would not be enough stuff for everyone, and people would disagree about who got what. Some people would fight each other, and everyone else would be very worried about their own safety. No one would be able to trust anyone else or make plans for the future. Life would be "solitary, poor, nasty, brutish, and short" (people would be alone, poor, mean, and would not live for long). Next, Hobbes argues that it would be a good idea for everyone to stop fighting and choose a Sovereign which could be one man or an assembly of men. Everyone should agree to obey the Sovereign, and give him all power of coercion or force of restraint under law. Once the Sovereign is in place, everyone has to obey him, even those who disagree with him. This is because everyone already agreed to obey him no matter what. Hobbes says it's better to be mostly safe under an all-powerful Sovereign, than to be in a state of war.