When so many prominent scientists and philosophers address a problem, which is obviously the case with the dimension problem, as can be seen in the preceding presentation (which is not even intended to be complete, but merely representative), one of two assumptions suggest themselves. Either it is a very fundamental problem concerning an important principle, or it deals with an illusionary problem which is difficult to recognize. After all, even illusionary problems can be extensively disputed. Therefore, we want to review the discussed approaches to spatial three-dimensionality with the following question in mind: can points be found to support the first assumption that a clearly specifiable problem, hence a philosophical task, exists?