Synthesized answer
The provided passages do not contain information that answers the question of what questions remain unanswered in "Plotin ou la Simplicité du regard" [1]. The passages only state the title and author of the book [1].
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
Title: Plotin ou la Simplicité du regard by Pierre Hadot Pages: 194