Comparing properties of brains and computers.

The criterion that pure natural science can only investigate objective phenomena which can be observed by independent observers sets certain limits to pure natural scientific understanding of brain functions. It excludes consciousness and feelings since these are only subjectively accessible and alternatives cannot be decided objectively. The limitations of brain research are discussed by comparing the properties of brains and computers. At least for the time being we do not know of any natural scientific--i.e. physical or chemical--method which allows the objective measurement of consciousness, sensations, and emotions. In addition it is discussed how and in how far our brain understands its surrounding nature.