All hierarchical concepts presented in this book, reflecting theories of brain function, behaviour and mental function, are based on a top-down approach. This means that pathological phenomena are the starting point for the conception of the hierarchical principle. The spectrum ranges from neurological disinhibition phenomena to neurologically induced atavistic behaviour in humans—and their homologies in animal behaviour—and to psychoanalytical concepts of psychopathological symptoms. Finally, the theoretical concepts of microgenesis are also based on observations of neuropsychological phenomena. In many cases, the bottom-up approach of contemporary neuroscience does not provide conclusive or only insufficient answers to physiological and pathological phenomena of human behaviour. Also, the aspect of subjective experience is almost completely ignored in contemporary neuroscience, so that for a number of specific human experiences, such as laughter, crying, habits of behaviour, dreams, humor, or psychopathological phenomena no coherent concepts exist. In contrast to this, a hierarchical-evolutionary approach provides comprehensive explanatory models not only for the function, but also for the disorders of the brain and behaviour.