The brain as a model of the world

My aim here is to show that an underlying assumption in computational approaches in cognitive and brain sciences is that the brain is a model of the world in the sense that it mirrors certain mathematical relations in the surrounding environment. I will give here three examples. One is from David Marr's computational-level theory of edge-detection. The second one is the computational work on the oculomotor system. And the third one is a Bayesian model of causal reasoning. One might wonder why this brain-as-a-model-of-the- world assumption is so prevalent in computational cognitive science and neuroscience. My proposed answer (for which I will not argue here) is that in these fields computation just means a dynamical process that models another domain. Thus saying that the brain computes just means that its processes models certain mathematical, or other high-order, relations in another domain, often the surrounding world.