Any attempt to explain or represent an experience is a theory, an idea of how certain event happen. Everybody uses theories; we cannot live without them. Our theories guide us in making decisions and taking actions, and they change from time to time as we observe new things ans acquire new perspectives. Our theories identify patterns of events in the environment so we know what to expect. They draw our attention to important aspects of everyday life. They help us decide what is important and what is not. And they enable us to predict what will happen next.