The following branches are the main areas of study
Metaphysics is the study of the nature of reality, including the relationship between mind and body, substance and accident, events and causation. Traditional branches are cosmology and ontology.
Epistemology is concerned with the nature and scope of knowledge, and whether knowledge is possible. Among its central concerns has been the challenge posed by skepticism and the relationships between truth, belief, and justification.
Ethics, or "moral philosophy", is concerned primarily with the question of the best way to live, and secondarily, concerning the question of whether this question can be answered. The main branches of ethics are meta-ethics, normative ethics, and applied ethics. Meta-ethics concerns the nature of ethical thought, such as the origins of the words good and bad, and origins of other comparative words of various ethical systems, whether there are absolute ethical truths, and how such truths could be known. Normative ethics are more concerned with the questions of how one ought to act, and what the right course of action is. This is where most ethical theories are generated. Lastly, applied ethics go beyond theory and step into real world ethical practice, such as questions of whether or not abortion is correct. Ethics is also associated with the idea of morality, and the two are often interchangeable.
Logic is the study of valid argument forms. Beginning in the late 19th century, mathematicians such as Gottlob Frege focused on a mathematical treatment of logic, and today the subject of logic has two broad divisions: mathematical logic (formal symbolic logic) and what is now called philosophical logic.