This chapter introduces the idea that psychology is a science that can and does—and indeed, must—pursue legitimate scientific methods to make progress. The nature of psychology invites people to challenge and extend the state of knowledge. The idea that the scientific theory might be wrong can take some getting used to. After the shock of discovering what psychology is like and learning to cope with methodology there is for many students another far more traumatic shock. One famous example is the field of research in psychology known as signal detection theory. The process of conducting scientific psychology entails much critical questioning and rigorous examination of theory, method, and conclusion. If an experimentally formulated solution fails to prove successful when applied back to the real world, psychologists are still in a position to reconsider and redesign an experiment to find the correct solution.