From the beginning, Greek philosophy was concerned with this reasoning process, particularly the process of rational demonstration . Most of this speculation concerned the nature of the changing, physical world. The early Greek philosophers were concerned with finding the unchanging principle or substance that lay behind all change and phenomena. Eventually, a wide range of activities would be subsumed under the category of philosophy, representing the entire range of human rational activities. The unifying factor was demonstration , that is, each activity was a philosophy in that it involved principles of rational demonstration.
Logic is really the core of philosophy.
Rhetoric Logic is a science of language, and so is rhetoric. While logic is the science of propositions and demonstration, rhetoric is the science of persuasion. It is less concerned with the truth of a proposition as it is concerned with using language, gesture, argument, and emotion to persuade other people of a truth or an opinion. For instance, if you conclude that God is behind everything in the universe, the study of God is a branch of metaphysics. Theology Theology is a branch of metaphysics and concerns the nature of the divine and the relationship of that nature to the physical, moral, and spiritual worlds.