What is it like to be a goldfish in a bowl? Does the curvature of the bowl distort its vision enough to prevent it from “knowing” anything beyond the water Can an “intelligent goldfish” make an “estimate” of the world beyond the bowl? What if human beings are in a globe as perception-distorting as the walls of the bowl for a goldfish?













This brings us to one of the fundamental issues regarding the nature of reality. Is what we see and what we hear “real”? If yes, how can we be we sure? If not, how can we know anything?

Naïve empiricism states that reality is what we experience through our sensory organs. This proposition has serious flaws in it. It cannot account for the vagaries of sense organ perception.

Although the only means by which we perceive the external world is through our sense organs, are we sure that what we see and hear are the only things that are “real”? Perhaps not.

Perception through sense organs skews the external reality according to the properties of the sense organs. For instance, the world of a dog would be a world of smell, while the world of humans is a world of colour. Furthermore, the brain reconstructs the sensory impulse in such a manner that we do not necessarily see the exact image presented before the sense organs. Thus, the external world is largely a consensual reality we share with fellow human beings by virtue of a similarity in the properties of our sense organs and the brain’s ability to reconstruct this reality. A part of the reason for violent differences of opinion amongst people may be due to biologically mediated differences in the properties of perception.

What is the nature of reality narrated by our sciences in such a scenario?

Stephen Hawking and Leonard Mlodinow give an elegant answer to this conundrum. Hawking and Mlodinow advocate a “model-based realism” that resolves all my issues with plain empiricism.

They start by telling the story of a goldfish in a curved globular bowl. Apparently, a city administrator in Italy had banned owners from keeping fish in curved globes, because they thought that the goldfish’s vision of the world outside the globe would be highly distorted. According to the town authorities it was cruel to expose the fish to a distorted view of the external world.

Hawking and Mlodinow ask a critical question of this situation – how are we sure our view of the world is not different from the distorted view of the fish in the globe? What if we are all hardwired to a computer and the reality as we see it, is all a software-feeling of our sense of reality? How can we decipher and differentiate such scenarios? The answer is that we cannot.

The goldfish can, nonetheless, determine the laws of motion of the objects outside the globe and make mathematical predictions. It will be correct in that the adjustment would be made for the curved movement of the objects seen through the globe. The mathematical equation needed to describe the movement of objects seen through the globe will be different from that seen from outside, but their fundamental properties would be the same. The difference between the physical laws as postulated by the goldfish in the globe from that observed outside the globe would be the adjustment in the equations made for the distortion of the respective “vision” (or rather, a distortion of light rays) in the globe.

Are our physical laws any better than the physical laws of the goldfish? The answer is no. Both give different representations of what they see from different frames of reference. This is the crux of a model-based realism of the world.

Model-based realism operates in our everyday life too. When we gaze at something, the clear portion of visual perception is only from a small area of 5.5 mm in the centre of the retina called macula, the rest of the images are all badly pixelated and blurred. Furthermore, the area in the optic nerve head where optic fibres condense and exit the eye does not have any sensory receptors and forms an area of “blind spot” in our field of vision of 7.5 to 5.5 degrees. However, none of us are aware of this blind spot in our visual field. This is because the brain takes all this badly processed data together and extrapolates the clarity of the macula to the whole field. This means that we are not made aware of the blurred images in the periphery of our vision and the blind spot in the centre of our visual spectrum.

To give another example by Hawkings and Mlodinow, suppose you are sitting in a classroom where there is a table and fan. If the reality is only what we see through our eyes, if you exit the room, the retinal images would have all ceased and it can seem like the table has “disappeared”. But the brain does not allow this discontinuity. It maintains the continued existence of the table for some period of time. If the fan falls down in the next moment and destroys the table, for the student who has maintained the image of the table in his head, the series of events are all well evidenced and reasoned. On the contrary, if the brain extinguishes the image of the table when you exit the room – in the absence of continued impulse from the retina- the scenario of the “fallen fan and the destroyed table” would be incomprehensible. For a moment there appears to be a nice looking table and fan; in the next moment there is a damaged table and fan. We don’t know what happened in between. In fact, for the idea of causality you need to have a model of a table and fan (all empirically disconnected) in your mind from the beginning to the end. Also, all this should emerge from a badly pixelated sensory input with black spots and movement artefacts.

The brain fixes the incomplete sensory input and provides a model-based recreation of the table – half of which you haven’t seen through your eyes, but was reconstructed from bits and pieces of the table and the fan.

This is model-based realism in our everyday life.

In other words, our reality does not directly come from the stimulation of our sensory organs from the external object, but in equal or greater measure from the brain’s recreation of e sensory inputs. We are able to vouch for the existence of an “external reality” because everyone processes the external reality more-or-less in a similar manner, and for a large part of our external reality, there is a consensus on how it looks. Thus, we have a consensus on what is green or what is yellow. But not for a colour-blind man. However, more complex objects (concepts) of consensus like morals and ethics have fifty shades of grey. Here, people diverge in uncanny ways that they cannot comprehend themselves. The almost intractable difference of opinion between conservatives and liberals and between liberals and libertarian is fuelled by layers and layers of differences in their models of perception.

Understanding the dynamics of model-based realism is a process critically important to achieve consensus, a process indispensable for civil peace and progress.

Although I am an agnostic , and a great believer of the empirical approach of science, I have serious doubts regarding the validity of empirical information to correctly know the nature of external reality. Movies like The Matrix that construct a scenario where people are artificially hardwired to believe they are living and enjoying life making free decisions became a tool to express my misgivings. My own understanding of cognitive neurology is that cognition creates realities that are not quite representative of the external world.

But as I read the first two chapters of the Grand Design by Stephen Hawking and Leonard Mlodinow, I found an answer that connected all the dots. Our reality is best described as a “model-based reality”. It may or may not be correct. We can never know. What is important to know is that it is consensual, without internal contradictions, and is enabled to create accurate theoretical predictions. If any of these characteristics fail consistently, it will be time to reform the model.

Clearly, the goldfish’s model of the universe would be as accurate as our model of the universe. Only, the equations and the derivations of its predictions would be different from that of ours. Its predictions of the world would be as accurate as the degree of its access to the world around. But yes, perhaps we are violating its “piscisian rights” by keeping it in a bowl alien from its natural environment. Or is it? Won’t it have acquired the neural connections to overcome the visual contours of the bowl? We don’t know.

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