أحدها: الغرض، أعني العلة الغائية
The first heading is the aim—that is, the final cause for pursuing the discipline.
Gharad denotes the intended objective. In logic, this may be expressed as learning rules that protect reasoning from error. That objective explains why the study is undertaken.
The aim should not simply be equated with every benefit someone may eventually receive. The distinction between an intended end and its useful consequences leads to the next heading.