Why would the brain flip the images perceived by your eyes? 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'.
It is not meaningful to talk about your brain processing something as 'right-side up&quot;' or 'upside-down'. The 'images' in your brain are just collections of neural activations, and not actual pictures. Thus they cannot have an orientation. The only meaningful way to test your question is to try flipping the input the brain receives and seeing if it can cope.
Fortunately, the brain is capable of flipping your visual field if required as measured through perceptual adaptation experiments using inversion glasses. This has been demonstrated very drastically in studies, by for instance requiring a participant to wear inversion glasses for a long time. At first they are confused, and unable to orient themselves and do basic tasks, however after enough time the brain can adopt enough to even do activities like riding a bike. This suggests that from the only way you can measure things (i.e. behaviorally) the brain is capable of adapting to an upside down world (some participants even reported that after extended use the world even seemed &quot;right side up&quot;). This is functionally equivalent to the brain being able to process your visual information in either orientation. If it is capable of processing in either orientation, the question of &quot;does my brain flip the image&quot; becomes a pseudo-question and unanswerable.
References

Taylor, J. G. (1962). The behavioral basis of perception. New Haven: Yale University Pres

Harris, C.S. (1965) &quot;Perceptual adaptation to inverted, reversed, and displaced vision.&quot; Psychological Review 72(6): 419-444. [pdf]]

Di Paolo, E.A. (2003) &quot;Organismically-inspired robotics: homeostatic adaptation and teleology beyond the closed sensorimotor loop&quot;, {Dynamical systems approach to embodiment and sociality: 19-42 [pdf