My PhD. description is the most classic definition. “His philosophical experience” means his own independent experience put into a philosophical format. A “philosophical format” means it needs a written Thesis. Please check the older generation of PhDs from Harvard, NY University etc. A university credit PhD. requires no academic pre-requisite, but needs another PhD or more than one PhDs from the university to recognize one’s achievement. The PhD applicant’s thesis has to reflect his/her own unique philosophy.