Some of the scattered essays:
Specifically, all the essays about the philosophy of education are philosophy, one in each domain.
The Apologia essay in the Theology section [Link] is philosophy. Essays about emotion in the Psychology section, [Link] to the extent that they are reflections on the nature of the human person, are philosophical. The Grammar section of the Literature section [Link] has some reflection on the grammar/logic/rhetoric division that is usually covered in philosophy, because Logic taught as introductory to philosophy.
In the Math section, any reflection on Gödel is philosophical. I may have one, or else I will!
In the Natural Sciences, all the discussions of creation, evolution, and of the truth-centered responsibilities of Galileo are partly philosophical in nature. [Link] In the Civics section, we are speaking of the nature of the human person and his responsibilities; that's philosophy. [Link] In the History section, the whole question of whether truth can be known is raised in a new way, one that is very important for a proper understanding of civics. [Link] In the Art section, we depend on a philosophical evaluation of the concept of beauty; it's not just subconscious and essentially irrational preference. [Link]
In the Music section, again, the concept and value of beauty is essential, as well as the concept of the human person. The essay linked here, on the topic of why God created men who were going to do very much evil, could have been linked on the theology page.
Some things will be cross-linked, some not. In your mind, everything is cross-linked, much more than you realize!