### Clue: I try latest in ontology, backing philosophy student (4)
### Answer: YOGI 
 ### Explanation: Definition: philosophy student
 **Reversal of**(…, backing) [I + GO(a try/an attempt at) + **last letter of**(latest in) "ontology" ].
Defn: …, that is, the philosophy of yoga, a school of Hindu philosophical traditions.
Answer: .., perhaps more of a practitioner than a student.