Augustine assumes here that in order for a person to find God, they must remember God somewhere deep in their memory; in other words, if they find him, they will recognize him as what they’ve been seeking all along. Augustine also assumes that true happiness is only found in God, and so people’s failure to find him suggests that they haven’t yet remembered rightly what true happiness is—that they have settled for a lesser form of happiness, perhaps misrecognizing it as true joy. Readers might pick up on how these ideas fit with Augustine’s account of his journey toward God, even if he doesn’t describe it exactly this way—that when God illuminates his mind in the garden in Milan, he suddenly knows beyond doubt that he’s found what he long sought.