Philosophy aims to search for meanings, truths, and principles through systematic theories about knowledge, truth, existence, causation, and good. It can be studied subjectively based on one's personal beliefs or more systematically through various philosophical approaches and branches. These include ontology concerning reality, epistemology regarding knowledge, and axiology involving theories of value like ethics and aesthetics. As a philosophy of education, idealism sees reality as consisting of ideas and seeks absolute truth, while realism views reality as objective and emphasizes rational inquiry and practical knowledge.