In this post, I would like to share some thoughts about Swampland. The idea behind the Swampland program is try to delineat some requirements imposed
on the matter sector such that it can be a UV completion theory when coupled to gravity sector. One of my favorate examples about these requirements comes from the work of Kim,Tarazi and Vafa, which imposed the upper bound, i.e. $26-d$ on $d$ dimensional supergavity with 16 supercharges. People would like to ask the priciples behind these requirements, or more precisely, consistency conditions of quantum gravity. In the past years, some ideas on these consistency conditions have been emergent.