How many triangles do you see in this picture?
Unless you’re being cheeky, you’d probably say five.
Now imagine that you take one of the small outer triangles - say, the one on the top - and slide it away from the group. You move that triangle somewhere else:
When you did that, what happened to the triangle in the middle? Where did it go?
Did it ever exist?
One answer is that none of these triangles “exist.” They’re only the result of context. When the circumstances around them change, we realize that they never had any inherent “triangle-ness” - that was just a temporary label we ascribed to them.
Similarly, you and I have conceptions of ourselves as people that are largely the result of context - who we work with, where we grew up, and what we eat for breakfast. We don’t exist in a vacuum. If you took away the causes and circumstances that make us who we are, my sense of “me” and your sense of “you” would be as empty as our sense of the disappearing triangle.
This is an explanation I learned from a Buddhist monk friend of mine. He’d tell you we exist, but only the same way those toothpick triangles do. It’s a way to keep things in perspective.
This is what the Zen "NO SELF" means.: Self does not exist as an independent, isolated, separate self-sustained living entity. We are all interconnected.