Theoretical Philosophy is the study of the principles for human knowledge, the development of the sciences and the basis for scientific knowledge, the principles of thought, argumentation and communication, metaphysics and the history of the subject itself. Some examples of the central issues we address are: what is knowledge and what is the difference between knowledge and information? What do logical thinking and rational argument entail? What does it mean to think critically? What ultimately exists? What does it mean that an event causes another? What characterises a scientific explanation? How should we change our views and theories in the light of new facts? What does verbal meaning involve and how does communication occur? To what extent is the human capacity for thought and communication unique?