Who or What are we?
From Joseph Goldstein:
"The Buddha described what we call "self" as a collection of aggregates – elements of mind and body – that function interdependently, creating the appearance of woman or man. We then identify with that image or appearance, taking it to be "I" or "mine," imagining it to have some inherent self-existence. For example, we get up in the morning, look in the mirror, recognize the reflection, and think, "Yes, that's me again." We then add all kinds of concepts to this sense of self: I'm a woman or man, I'm a certain age, I'm a happy or unhappy person – the list goes on and on.
When we examine our experience, though, we see that there is not some core being to whom experience refers; rather it is simply "empty phenomena rolling on." It is "empty" in the sense that there is no one behind the arising and changing phenomena to whom they happen. A rainbow is a good example of this. We go outside after a rainstorm and feel that moment of delight if a rainbow appears in the sky. Mostly, we simply enjoy the sight without investigating the real nature of what is happening. But when we look more deeply, it becomes clear that there is no "thing" called "rainbow" apart from the particular conditions of air and moisture and light.
Each one of us is like that rainbow -- an appearance, a magical display, arising out of our various elements of mind and body."