Interesting topic. Yes, apparently there are 8 types of love theorised by Greek philosophy, not just four.
A quick Google search shows even some other sites about philosophy, love or psychology only refer to 5 or 6, so there seems to be some confusion or cherry-picking about the exact number that "matter", but it appears the total number was 8:
- Agape - unconditional love
- Eros - romantic love
- Ludus - playful love
- Mania - obsessive love
- Philautia - self-love
- Philia - friendly love
- Pragma - committed love
- Storge - familial love
Except... again, a ninth type is mentioned in the Wikipedia article on the subject, which leaves out three of the others (Ludus, Mania, Pragma), giving only a total of 6:
So was it 8 or 9? Perhaps a Greek, or someone with knowledge of Greek philosophy, will be able to clarify?
I did a quick search of the WT online library and can find no mention of "Pragma" or "Xenia" on there, but 88 for "Agape", a dozen for "Storge" and even about 40 for "Eros".
While I can understand that Ludus, Mania and Philautia are not mentioned by the GB, it's curious that the org has never made mention of Pragma or Xenia, since they seems to fit well with Christian principles. Yet the GB never even mention them in passing.
EDITED: I discovered later that "Xenia" is also known as "Philoxenia" - love of strangers. Apparently, the latter word IS in the WT online library about six times on the subject of hospitality. Still no "Pragma" though!