  To understand what the thought, ‘providence or atoms’, is doing here we have to connect it with the discontent that is the topic of the passage. Marcus is admonishing himself for his discontent with things as they stand, saying to himself, ‘if you are finding fault with things as they are, then you must think that they are not due to providence. But if they’re not due to providence, then they’re the result of random causes.’ In this passage, ‘atoms’ functions as the implicit commitment of one who finds fault with things as they are. The reasoning works to raise the stakes for someone who is grumbling at the way things are. It brings out that there is a contradiction between believing, as a Stoic must, that the world is providentially run, and being discontented with anything that happens. Once the contradiction is brought out, it becomes clear which of the two alternatives a Stoic must plump for, and what follows about the attitudes he must consequently adopt towards the world and every part of it. Sometimes Marcus spells out these steps: ‘But look at the evidence in favour of providence—the whole cosmos is organised like a city, that is to say, each part is so organized as to serve the good of the whole’. For example, at iv.27, Marcus appears to be starting to consider the twin possibilities that the world is a cosmos or a chaotic mixture (kukeôn, referring perhaps to Heraclitus fr. 125), but then he immediately asserts that it is a cosmos. Often, however, Marcus does not have to spell this out. In any event, what ‘atoms’ stands for, in this context, is impiety. So Marcus is telling his grumbling self: your grumbling is evidence of impiety, evidence of your being like an Epicurean—except that actual Epicureans are more philosophical and do not grumble about an irrational cosmos bringing them bad luck, but rather, try themselves to live rationally.