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 wh