In the Middle Way (Madhyamaka) school, there are two modes of existence: one is true existence, that is, things really exist; the other is nominal existence, that is, things exist from a conventional standpoint but not inherently. That which truly exists is called “self.”

The “self” in “self in person” connotes “I, me” to some extent, for instance, “I want to make money,” “I want to go to work,” “I want to have a good life,” “I want to have a long and healthy life,” etc. The “self” in “self in phenomena” is entirely different; it only denotes true existence.

- Quote from The Four Seals of Dhama, "All Phenomena Lack Self-Existence"