Hallucinating reality

As we have seen in my last two blogs, in our brain we have no direct picture of the world around us. Our image of the world is no copy of the world but it is a constructed image that represents mainly what is relevant for us. Rays of light touch our eye. Already in the eye certain types of light are selected. We see no infrared or ultraviolet, while bees do, for example. Then the light impressions are transported to our brain, not as rays but as chemical and electrical signals. There the final image is constructed by a complex mechanism in our head. Information can be lost in this way but can be added, too. I think that many people know the idea of Gestalt. Three separate points arranged in the shape of a triangle are seen as a triangle, although there may be no objective reason for it. We just think that the three points form a triangle. Therefore, we can also say that we simulate a triangle. In this way, what we see is actually a simulation in our head. This simulation needs not to be a real image of the world, but it is one we think that it might be so: It represents a possible world.
The simulations of the world around us, of the “real world”, are not the only possible worlds we have in our heads. We have dreams, fantasies, hallucinations, inner monologues, plans for the future, images of ideal worlds, and so on. All these simulations represent a world as it might be, a possible world constructed by the brain on the basis of information stored there but maybe also based on (or partially based on) false information, or even caused by disturbances of the brain. The only difference between a simulation of the real world and the other simulations is, as Thomas Metzinger says it, that the first one “simulates … a ‘Now’ ” (Metzinger, Being no one, p. 50).
Metzinger points to the fact that idealistic philosophers have seen this clearly. And if representations of the real world are not fundamentally different from the other kinds of simulations and if all simulations are produced by the brain, it is only one step further to see all simulations, including the simulations of the real world, as kinds of hallucinations. However, there is an important difference between the other hallucinations and the hallucination of the world around us: A simulation of the real world is continuously checked and updated with new information, while the other hallucinations are not or only now and then. As Metzinger formulates it (p. 51), our images of the world around us are online hallucinations, while the other kinds of simulations are hallucinations offline.