Ritual Aptitude is a depreciated 3e advantage that was woven into Magery in the 4e Ritual Magic system

Hellboy Sourcebook and Roleplaying Game allowed Clerical Investment to substitute for it to remove the -5 for casting some Path of Spirit rituals, but not for removing the skill cap of 12.

Also since this allowed casting without the Ritual Magic skill, the Path of Spirit skill could be selected without that prerequisite.