Augustine asks to know God as well as God knows him. God knows Augustine's heart. Why then does Augustine confess before his readers? They cannot know Augustine's heart, but in Christian charity, they will know he tells the truth. By his example, his fellow believers will be moved to thank God and to change their own lives if they are in despair. Even Augustine cannot know himself fully, and he cannot know God fully. He inquires how he can know God. The physical world testifies to its creator, but the physical world is not God. Even animals have senses to perceive the world, but they cannot apply reason to lead them beyond physical things. The human soul orders the perceptions of the senses, but Augustine must ascend beyond this function, to memory.
Memory stores not only sense perceptions but also skills and ideas, which are not apprehended through the senses. Learning is the process of gathering and ordering all these notions in the memory. Mathematics is purely abstract, incapable of making sense impressions, but the memory can hold it. Emotions, too, can remain in the memory, although they have no existence outside the mind. People only remember those emotions, rather than feel them anew. The images of all these things are present in memory, but what about the idea of memory itself, or the idea of forgetfulness? How can I remember "forgetfulness" if forgetfulness is the very act of not remembering?
The power of human memory is vast and awesome, but how can one move beyond memory to knowledge of God? If you forget something, you can look for its image in your memory, if only partially. All people want to be happy, but how do people know of happiness? True happiness is only with God. Human beings mistake earthly happiness for the happiness found in God; people hide from this truth and so become miserable. God is not a sense perception, an emotion, or even the mind itself, but God remains in the memory.
