You might not be aware of the fact that right now where you are standing, you are not only in one but two mental spaces simultaneously: the gallery-space of Mental Space and a kind of mental space that is beyond and around your body. It is an egocentric co-ordinate space with your body at its center but also a space that is enclosed by your physical skull.
You read this text on the surface of a white wall that you are perceiving with the help of your eyes. Both the wall and your eyes as body-parts are positioned in space relative to each other. Yet, to characterize this space, ‘physical’ might not be the right choice of adjective. According to the viewpoint presented here, ‘physical space’ by definition is only to be described in the formal language of mathematics as it is used in physics. Therefore, you, from your subjective first-person point of view, occupy a space that is not the objective space postulated by physics but the space-as-perceived-and-experienced by you, that is, a ‘mental space’ — better to be called as ‘phenomenal space — that is constituted by your nervous system. In physical space, the railroad tracks do not meet at the horizon, in phenomenal space, they do. In physical space, there are no optical illusions, in phenomenal space there are. In physical space, one cannot find afterimages, in phenomenal space one can experience them frequently. In physical space, no visual hallucinations occur, in phenomenal space they might do. And in the long run, phenomenal space cannot contain mind-independent physical objects-in-themselves but only mind-dependent objects-as-perceived, that is, ‘mental objects’ of some sort (preferable to refer to them as ‘phenomenal objects’). Therefore, these words that you are reading at the moment are not on the surface of a physical but a phenomenal object, a phenomenal wall, so to speak. In fact, this phenomenal wall is no more than a bundle of qualities organized into a particular pattern with the meaning you cannot help but attribute to it during the perceiving and interpreting processes that occur in your brain and happen to you as a person. Among the phenomenal objects as this phenomenal wall there is the one that enjoys maximal priority for you as this object is your own body known by you, both from the outside and inside, the body-as-perceived-and-experienced by you, your lived, ‘phenomenal body’. And undoubtedly, the most crucial body part of your corporeal existence is your phenomenal head. However, your phenomenal head is in fact mis- as well as under-represented by your physical brain.
Clearly, you are not experiencing two separate channels of vision originating from your two physical eyeballs but a unified picture. It is as if you were looking through a cyclopean aperture somewhere midway between your two real eyes — it feels as if you had a single eye a few centimeters behind the bridge of your nose, a location that is called the visual ego center that can be established by using the basic tenets of Ewald Hering’s projective geometry¹. However, the problem with this configuration is that sensation of occupying a position in space from which you perceive the world ‘out there’ designates an impossible location, in other words, the egocenter as a placeholder for a cyclopean eye would be useless with which one would see nothing other than a pitch-black manifold, since, to repeat, it is deep enough under your skin to be actually in your brain, surrounded as it were,
by neural tissue on all sides: “the cyclopean aperture is
a convenient neural fiction through which the distal visual world is ‘inserted’ through a missing part of the proximal visual body”.² The egocenter is nevertheless the evidence that your phenomenal head is experienced not as you would expect from the outlook of your physical body since it seems as if there were an oval hole on your upper face-region in your phenomenal head. In sum, both the phenomenal wall whose surface you are looking at to read this text and the phenomenal body with the ego center from where your seeing seems to be done from resides in phenomenal space. However, this phenomenal space should also be located somewhere. So, where is this phenomenal (mental) space of yours? Is it in physical space?
To put it somewhat bluntly, the space in which you experience yourself to be located is in fact the physical space of your physical brain. This means that if you could see through the walls, the floor and the ceiling of this room, you could see the inner surface of your physical skull with its flesh and bone architecture as it would look like from the inside.³ Therefore, the copy of your head is in a copy of the world in the inner space of your true physical skull. Your experience of being present in the world ‘out there’, as located in the 3D space of your physical surroundings is merely an illusion of a special kind, the fundamental, constitutive Out-of-Brain illusion.⁴
¹Merker, Björn. Consciousness Without a Cerebral cortex: a Challenge for Neuroscience and Medicine. Behavioral and Brain Sciences, 2007 Feb;30(1):63-81; discussion 81-134.
²Merker, Björn. Consciousness Without a Cerebral cortex.
³Lehar, Steven. The World in Your Head: A Gestalt View of the Mechanism of Conscious Experiences. Lawrence Elbaum: New Jersey. 2003.
⁴Revonsuo, Antti. Inner Presence: Consciousness as a Biological Phenomenon. MIT Press: Cambridge. 2006.