The writer of the hupomnemata or zettelkasten is not outside what is recorded. They are what is recorded. They are forming themselves and can not be separated from themselves.

When you write, it produces your identity, and when you take a pen to paper or have your finger dance on a keyboard, you spill out who you are.

Hupomnemata is a Greek term for collecting ideas from what is heard and what is read. Zettelkasten is a German term for corralling ideas into notes from what is heard and what is read. Both are used to synthesizing, incorporating, and solidifying what is read and heard into life.

We are continually taking in inputs from outside of us; rather, we acknowledge it or not. What we are exposed to. What we choose to do at any moment. Everything we read, see, feel, and all our interacting are continually being synthesized, incorporated, and solidified by our minds. They influence who we are and then put us on a path to who we will become. This makes it doubly important to read life-affirming books and associate with positive people who can help you grow. You don't want to synthesize anything that is negative or stifles you into your life.

Thus, every man, in the course of his life, must not only show himself obedient and docile. By his fidelity, he must build—starting with the most natural territory of his own self—a work, an opus, into which something enters from all the elements of the earth. - Mary Sarton - Journal of a Solitude

Michel Foucault stressed the connection between keeping a Hupomnemata/Zettelkasten journal and "care of the self." Equating this care of the self with integrating ideas in the path of my life,

There is a difference in content and the target for a Hupomnemata/Zettelkasten and the Autobiographical Journal. The former is concerned with learning and is written for the writer. The latter is a record of past experiences and is written for the reader.

Reference
Foucault and the Hupomnemata: Self Writing as an Art of Life - Author - Matthias Swonger