[Bromskloss]

What section of it should I read to get an idea of what, according to the author, "philosophy of computer science" is?

[dredmorbius]

Start with the ToC, as suggested. It provides an excellent overview and framework.

The first four chapters (and preface) largely answer this question. Though of course, the answer is what the entire book is about.

[kd0amg]

The table of contents is surprisingly thorough in covering this topic.