The following is a common scientific statement, which you don't have to google long for to find:
The eye views images upside-down in the manner of a camera lens, but our brains reinterpret this input to allow us to see things the correct way up.
My first question is quite straightforward: Is this statement valid?
I don't understand why you should come to the conclusion that your brain should 'flip' the image. Wouldn't your brain be able to cope just fine without flipping it? If anything I would suspect the brain to not flip the image, if there is no reason to do so.
In order for this statement to be valid, I would expect a scientific theory/experiment from which can be concluded that the brain does process the vision in such a way that, after it being processed all subsequent processing occurs on the 'inverted' image. That seems to me to be the most logical interpretation of 'to flip'.