"The old doctrine of an inner sense with the involved idea of a distinction between the reality of consciousness and objectivity must now have its opportune renewal in the domain of psychology. This is the principal conclusion I would draw from my experiments. In connection there with I define abstraction as the process by which the logically or psychologically effective is separated from the logically or psychologically ineffective. The effective partial contents are positively abstracted for thinking and ideation. The ineffective are those from which the abstraction is made. For our consciousness, therefore, there are abstract ideas, for psychical reality there are only concrete ideas. At the same time the old controversy between nominalism and realism approaches its solution."