My previous riddle was solved in about a day. So I thought of getting a little philosophical with this one. You can still try my previous riddle here. Give it a try if you haven't and check the comments for the answer.

I thought of doing about 2 or at least one of these posts each week. This is the second one for the week. This riddle is based on a Buddhist story I've heard. The solution has a lot of philosophical and spiritual depth. It's also a very very clever one like solving a paradox (https://steemit.com/philosophy/@vimukthi/relational-quantum-mechanics-solution-for-the-paradox-of-the-ship-of-theseus-with-a-touch-of-zen-and-cryptocurrency)

Here goes the question:

You are a person of great wisdom and spiritual development living alone in the forest. A great and undefeated debater comes to the nearby city. He's extremely clever. Think of the best lawyer you can think of. Logic is practically his bitch and soon establishes himself as the greatest intellectual of the area. (This may remind you a little of The Ip Man movies.) A somewhat wise and intelligent person who knows you meets the debater in public and declares that you who is living in the nearby forest is far wiser and spiritually developed. 

The great intellectual takes on the challenge and comes to the forest with great confidence. He meets you and quickly let you know he has come to test your reputation. You being the nice, kind and relaxed person points to the river that flows from north to south and ask the debater to drink some water and refresh himself after the long journey.

Wanting to royally crush you he quickly ask you a question.

O Dear wise one, should I drink from the West bank or the East bank or from the middle?

The intellectual debater can drag the conversation in any direction. He can argue against any answer you give. If you say there is no right answer, he can claim that you simply doesn't know an answer and is trying to get off with a easy knee-jerk answer.

The story I had heard has a single answer that upon hearing the debater pretends to goes to the river and never return for the debate. (He got convinced that there is no way he could compete with such a great mind.)

The riddle is to come up with the answer that was given. It's tricky, philosophical and devilishly clever. Don't use the internet. Think on your own. 

Best of luck!