Objections to the possibility of understanding our mental life – Federica Francesconi

Objections to the possibility of understanding our mental life

Federica Francesconi


02.04 – 30.04 2021


One of the most fascinating recent advances in neuroscience concerns the functioning of our visual system: how do we see? How do we know from a glance that there is a book or a cat in front of us? It would seem natural to think that receptors detect the light that arrives on the retina of our eyes and transform it into signals that run towards the inside of our brain, where groups of neurons process information in a more and more complex way, up to interpret it, and identify objects. Neurons recognize lines that separate colors, other neurons recognize shapes drawn by these lines, others compare these shapes with memory data … still others come to recognize something: it is a cat. But no. The brain doesn’t work like that. It works in reverse. Most signals do not travel from the eyes to the brain – they travel in the opposite direction, from the brain to the eyes.
What happens is that the brain expects to see something, based on what has happened before and how much it knows. Create an image of what your eyes expect to see. This information is sent from the brain to the eyes through intermediate stages. If a discrepancy is detected between what the brain expects and the light reaching the eyes, only then will the neural circuits send signals to the brain. That is, from the eyes to the brain, the image of the observed environment does not travel, but only the news of any discrepancies with respect to what the brain expects. The conceptual implications on the relationship between what we see and the world, however, are considerable. When we look around we are not really “observing”: we are rather dreaming of an image of the world based on what we knew ( including wrong prejudices) and unconsciously we scrutinize to detect any discrepancies and, when necessary, try to correct. What we see, in other words, is not a reproduction of the outside. This is what we expect, corrected by what we are able to grasp. The relevant inputs are not the ones that confirm what we already knew. They are the ones who contradict our expectations.

Carlo Rovelli, Helgoland



Photography courtesy of Rein Kooyman