What is the basis of naming a baby after a deceased person?
In fact writes Rav Yehudah Fetaya in Minhat Yehudah that this should be discouraged (especially if were not sure if he/she was 100% perfectly righteous and needs to atonement).
Answer:
There is an element of kibbud av va-eim in calling a person after a deceased person.
Based on sources in kaballah there is possibly a connection between the soul of the named and the soul of the person named after.
In any case, this is the common custom among Jews of virtually all groups and demominations, and therefore it should surely not be snuffed at.
Many responsa have been written about calling after those who died young or unnaturally, which demonstrates how widespread and entrenched the practice was.
See Maharshal, Gittin Chap. 4, concerning this questions; Iggros Moshe, Yoreh De’ah 2:122; Mishnah Halachos 6:258; Yabia Omer 5, Yoreh De’ah 21.
