Stoicism was a group of philosophers in the First Century who made laws that they thought should be followed by the citizens of Rome. Two of these laws were the concepts of rationality and nature. Marcus Aurelius was the Emperor of Rome at the time and he also the most known Stoic. His concepts were vital to the survival of the Stoics. .
The concept of rationality is what tells a human being what's right and wrong and what should be done and what is good for the human and the state by thinking. "the reason also, in respect which we are rational beings, is common: if this is so, common also is the reason which commands us what to do, and what not to do; if this is so, there is a common law also; if this is so, we are fellow citizens; if this is so, we are members of some political community; if this is so, the world is in manner of a state."(1) Marcus Aurelius says here that the citizens who are ration beings as a part of the whole political spectrum, should combine to make he world one state. He wants the world to join as one state and governed by one, the people are all part of the same political system, so they should join together. .
In his Meditations Aurelius talks about every action having a purpose. "Let no act be done without a purpose, nor otherwise than according to the perfect principles of art."(2) He says here that the reason we have is because everything we do has a purpose. The purposes are there because they are the unwritten rules of art. These rules are abided because they just happen. The art sets its own rules through the purposes of the acts that are done. No act should be done if it does not follow the rules of art. Yet, the rules of are made by the act's purposes. This meaning everything has a reason why it is done and the purposes are legitimate.
A man's life does not become worse unless he makes it worse. "That which does not make his life worse, nor does it harm him either from without or with in.