Ab Initio nuclear physics: proceeding from the "bottom up"

The Holy Grail of nuclear theory is the ab initio description of all (finite) atomic nuclei and (infinite) nuclear matter. The past 20 years have seen great progress towards this goal. However, around 2015, the program hit a stumbling block, when it turned out to be difficult to explain the properties of intermediate-mass nuclei and nuclear matter simultaneously. Solutions to this problem have been advanced, and we will analyze to what extent these solutions can be perceived as genuine ab initio.