What does 1周まわって mean in this context?

Question

Context:

Person A is a modern person who was transported to a parallel world where people are still in the middle ages. Person A assumes that the present Earth is round and he explains to person B that it is a magnetic sphere with a north pole and a south pole. Person B neither knows about this nor believes in it.

Person B: 世界は玉じゃないよ

Person A: ...もう1周まわって そっちが真実かもしれんな

The conversation ends here.

Now, I can't make sense of the last sentence. Who possibly could do the 回る here?

Answer 1

It's used when you accept something even if you don't think it's honestly good, such as when you think "that's weird" but you can't help yourself laughing because it's funny.

The phrase "一周回って" can be used to acknowledge a comment that would generally be regarded as bad, but statement is still so to the point that it makes sense.

The phrase "一周回って" is used in the same way as the slang term "逆に". It's not strictly "逆", since 一周(roundabout) = 360 degrees and 逆(opposite) = 180 degrees, though it's a well-established usage.

Side note: It's also used to say that you have come "full circle".

For example, let's say that you liked Girl A at first, but then you changed your mind to Girl B and stayed away from Girl A for a while.

But when time passes and you looked at Girl A again, you feel that she is good again. When you look at other girls, but you still like Girl A, you say, "一周まわったけど、やっぱりAが好きだな".

Answer 2

This type of 一周回って is an expression used when someone started thinking the other way round, or started to have a completely different impression after looking at something extreme for a while. Imagine you are running a race without knowing the course was a loop. You're thinking you are running in the lead, but eventually you'll notice you are chasing the last person. Whether you are running forward or backward, you eventually reach the same location.

In your case, person A has believed the earth is round also in this isekai, but noticed there was nothing to prove it objectively. After all, he knows little about how physics work in this new world, so blindly believing the world is round could be as wrong as believing the world is flat. He thought he was the most knowledgeable, but he realized he could be the least knowledgeable. That's why he said 一周回って.

Other simpler examples can be found in this question. Other examples include:

• 最初は彼が勝つと嬉しかったが、あまりにも強いので一周回ってつまらなくなってきた。
• あの芸人のギャグは嫌いだったが、あまりに同じネタを繰り返すので一周回って好きになってきた。