Commentary on Meditations: B8:52-53

Someone who does not know that there is an ordered universe does not know where he is. Someone who does not know the natural purpose of the universe does not know who he is or what the universe is. Someone who fails in any one of these ways could not tell the purpose of his own existence either. So what do you think of the man who fears or courts the applause of an audience who have no idea where they are or who they are?

Do you want the praise of a man who curses himself three times an hour? Do you want to please a man who can't please himself? Can a man please himself when he regrets almost everything he does?

What is the purpose of the universe; this world?  From this passage, we can tell that in Marcus' opinion, the purpose of the Universe and world is the same as the purpose of a human.  Why do we exist?  What should be our aim?  Pierre Hadot says in his book The Inner Citadel (p. 161),

For [the Stoics], the only important thing is humankind's moral elevation and its quest for wisdom. Divine providence, creative and nurturing toward inferior creatures, becomes the educator of human beings.

He goes on to cite Henri Bergson who once said (source),

Men do not sufficiently realize that their future is in their own hands.  Theirs is the task of determining, first of all, whether they want to go on living or not.  Theirs is the responsibility then for deciding if they want to merely live, or intend to make just the extra effort required for fulfilling even on their refractory planet, the essential function of the universe, which is a machine for the making of Gods.

Knowing that our purpose is to become moral & wise beings (the Stoics called them sages), we need not have a high regard for others who think the purpose of humans is to seek applause.  And furthermore, we should not have a high regard for any of those who don't think the purpose of humankind is morality and wisdom.

In the next passage, Marcus further elaborates on who we seek praise from.  We need not worry about seeking praise from anyone who is never happy or content or who lives in constant regret.