Magnetic resonance imaging methods have taken a commanding position in brain studies because they allow scientists to follow brain activities in the living human. The ability to measure cerebral anatomy, neuronal firing and brain metabolism has extended and re-invigorated hopes ofunderstanding the role that brain activity plays in human life. The brain has assumed a central role in our thinking of the world that can be traced back to the philosophies that are expressed in psychology, religion, literature, and everyday life. Brain scientists, planning and measuring brainactivities by imaging methods, have consciously or unconsciously been influenced by these philosophical views. This book, in describing the experiments using imaging methods, traces how assumptions about the nature of brain function made in planning scientific experiments are the consequences of philosophical positions. Experiments that relate brain activities to observable behavior are shown to avoid thephilosophical and psychological assumptions about mental processes that have been proposed to underlie these behaviors. These promising, empirical experiments are consistent with the philosophy of Pragmatism which, in judging hypotheses about understanding by their consequences, has questioned thevalue of everyday conceptualizations of brain activity for imaging studies.