Traditionally, philosophers of science have distinguished between a context of justification and a context of discovery . The first was conceived as the proper field of application of philosophy of science, while the second was regarded as concerning scientists, not philosophers. Contemporary thought believes that the context of justification forms a continuum with the context of discovery and, as a result, that observation and experimentation have become an important field of inquiry. This volume is meant as a contribution to the ongoing debate on this topic. It is meant for researchers and advanced students in philosophy of science, and for natural and social scientists interested in foundational topics. It combines the viewpoint of philosophers and scientists and casts a new interdisciplinary perspective on the problem of observation and experimentation. It spans a wide range of disciplines, including physics, economics and psychology.