"I don't know... the White Witch sent him to that garden. The poem warned about despair. Despair ensued. Maybe they're perfectly benign apples of immortality and Winter is just separately doomed, maybe being sent by the Witch was what caused his problem, maybe there are more factors at work that I don't understand, maybe there's an interpretation of the poem that shows how to use them safely... and maybe they're cursed apples that make you immortal at the cost of eventually ending up helplessly suicidal for the rest of eternity. I don't know, and I don't know how to find out, and I don't want to risk it without better information."