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| Thomas Nagel wondered if the world a bat perceives is fundamentally different to our own |
By Keith Tidman
Do we experience the world as it objectively is, or only as an approximation shaped by the effects of information passing through our mind’s interpretative sieve? Does our individual reality align with anyone else’s, or is it exclusively ours, dwelling like a single point amid other people’s experienced realities?
We are swayed by our senses, whether through the direct sensory observation of the world around us, or indirectly as we use apparatuses to observe, record, measure, and decipher. Either way, our minds filter the information absorbed, becoming the experiences funneled and fashioned into a reality which in turn is affected by sundry factors. These influences include our life experiences and interpretations, our mental models of the world, how we sort and assimilate ideas, our unconscious predilections, our imaginings and intuitions unsubscribed to particular facts, and our expectations of outcomes drawn from encounters with the world.
We believe that what serves as the lifeline in this modeling of personal reality is the presence of agency and ‘free will’. The tendency is to regard free will as orthodoxy. We assume we can freely reconsider and alter that reality, to account for new experiences and information that we mold through reason. To a point, that’s right; but to one degree or another we grapple with biases, some of which are hard-wired or at least deeply entrenched, that predispose us to particular choices and behaviours. So, how freely we can actually surmount those preconceptions and predispositions is problematic, in turn bearing on the limits of how we perceive the world.
The situation is complicated further by the vigorous debate over free will versus how much of what happens does so deterministically, where life’s course is set by forces beyond our control. Altering the models of reality to which we clutch is hard; resistance to change is tempting. We shun hints of doubt in upholding our individual (subjective) representations of reality. The obscurity and inaccessibility of any single, universally accepted objective world exacerbates the circumstances. We realise, though, that subjective reality is not an illusion to be casually dismissed to our suiting, but is lastingly tangible.
In 1974, the American philosopher Thomas Nagel developed a classic metaphor to address these issues of conscious experience. He proposed that some knowledge is limited to what we acquire through our subjective experiences, differentiating those from underlying objective facts. To show how, Nagel turned to bats’ conscious use of echoed sounds as the equivalent of our vision in perceiving its surroundings for navigation. He argued that although we might be able to imagine some aspects of what it’s like to be a bat, like hanging upside down or flying, we cannot truly know what a bat experiences as physical reality. The bat’s experiences are its alone, and for the same reasons of filtering and interpretation, are likewise distinguishable from objective reality.
Sensory experience, however, does more than just filter objective reality. The very act of human observation (in particular, measurement) can also create reality. What do I mean? Repeated studies have shown that a potential object remains in what’s called ‘superposition’, or a state of suspension. What stays in superposition is an abstract mathematical description, called a ‘wavefunction’, of all the possible ways an object can become real. There is no distinction between the wave function and the physical things.
While in superposition, the object can be in any number of places until measurement causes the wavefunction to ‘collapse’, resulting in the object being in a single location. Observation thus has implications for the nature of reality and the role of consciousness in bringing that about. According to quantum physicist John Wheeler, ‘No ... property is a property until it is observed’, a notion presaged by the philosopher George Berkeley three centuries earlier by declaring ‘Esse est percepi’ – to be, is to be perceived.
Evidence, furthermore, that experienced reality results from a subjective filtering of objective reality comes from how our minds react to externalities. For example, two friends are out for a stroll and look up at the summer sky. Do their individual perceptions of the sky’s ‘blueness’ precisely match each other’s or anyone else’s, or do they experience blueness differently? If those companions then wade into a lake, do their perceptions of ‘chilliness’ exactly match? How about their experiences of ‘roughness’ upon rubbing their hand on the craggy bark of a tree? These are interpretations of objective reality by the senses and the mind.
Despite the physiology of the friends’ brains and physical senses being alike, their filtered experiences nonetheless differ in both small and big ways. All this, even though the objective physical attributes of the sky, the lake, and the tree bark, independent of the mind, are the same for both companions. (Such as in the case of the wavelength of visible light that accounted for the blueness being interpretatively, subjectively perceived by the senses and mind.) Notwithstanding the deceptive simplicity of these examples, they are telling of how our minds are attuned to processing sensory input, thereby creating subjective realities that might resemble yet not match other people’s, and importantly don’t directly merge with underlying objective reality.
In this paradigm of experience, there are untold parsed and sieved realities: our own and everyone else’s. That’s not to say objective reality, independent of our mental parsing, is myth. It exists, at least as backdrop. That is, both objective and subjective reality are credible in their respective ways, as sides of the whole. It’s just that our minds’ unavoidable filtering leads to the altering of objective reality. Objective reality thus stays out of reach. The result is our being left with the personal reality our minds are capable of, a reality nonetheless easily but mistakenly conflated with objective reality.
That’s why our models of the underlying objective reality remain approximations, in states of flux. Because when it comes to understanding the holy grail of objective reality, our search is inspired by the belief that close is never close enough. We want more. Humankind’s curiosity strives to inch closer and closer to objective reality, however unending that tireless pursuit will likely prove.
7 comments:
If I read this right, Keith is saying that there IS an objective reality, but it is always out of reach. Instead we see many different false realities. That's really Plato's argument, isn't it? But as someone said, what purpose does this 'reality' serve in such a scenario? Why not just do away with it, per the spirit of not inventing entities that have no practical - or explanatory- purpose?
First as a matter of interest, looking at the image, we have bats in our pad in central Cape Town. They squeeze through the air bricks, and vanish if one makes the slightest sound. I only once saw one, wriggling out of our lounge, but they leave evidence of their presence everywhere. We decided to let them be.
Whatever the world out there is, we surely don’t have direct access to it. What we have access to is a reality which has already been translated into a form which exists in neural networks. We have access to the map, but not the territory. In fact I suspect that the world may really be about something quite different to what we think, but we may never discover it.
You raise an interesting point, Martin. To answer, I think we start with these two facts, for context: First, that our species has senses and a mind, both products of human evolution. And second, that the network that comprises those senses and the mind performs in ways that filter and interpret the world, whose product is our experiences. To call this physiological network and its functions an ‘invention’ is a mischaracterization, in contradiction to their evolutionary origins. So, I believe that the question can, and should, be rephrased as this: ‘Why did the human species evolve to have a system of senses and a mind that filters and interprets its surroundings?’ This ontological question about the very nature of our being for now remains rhetorical, of course. But the important takeaway is that the very behaviours of this evolutionarily derived system unavoidably, and by definition, lead us to an interpreted (subjective) reality, not the backdrop of objective reality.
Nice summary, Thomas, regarding the inaccessibility of the objective world, in light of the nature of the ‘neural networks’ you cite, and how we therefore necessarily default to the ‘translations’ of that world to which you refer.
The question then becomes, I think, what constitutes that which is real in a neural network? Any concept with a label, presumably, will be real TO ME. Say, a chair. Or citizenship. Or God. One needs now to define which phenomena, in the Kantian sense, are real, and which not. In the interim, thank God, Keith has restored the reality of religion.
You’re welcome, Thomas. ;-)
However, what with the presence of things like cathedrals, baptismal fonts, confessionals, pulpits, stained-glass windows, and so forth — all of which can only ever be interpretatively experienced by the senses and mind, resulting in individual subjectivism — I don’t believe the ‘reality of religion’ was being refuted here. Therefore, there is no effort, at least by me, to ‘restore the reality of religion’, as you too kindly put it. On the other hand, I propose that supernatural beings — the key ingredient missing from the discussion here — are surely a better fit for my previous essay on ‘unknowability’.
Very thought provoking Keith. Each person's perception of reality is their own, based upon, as you say or imply, the sum total of their knowledge/learning and experiences to that point in their life. An individual's reality is only theirs and whether it is accepted by others is the real question in human existence.
As your final paragraph so eloquently states "objective reality" is in the eye of the beholder, each having to seek it individually given the sum total of their knowledge and experiences (or lack there of).
I'll quote Rebecca Solnit a Guardian US columnist whose most recent books are "Recollections of My Nonexistence" and "Orwell's Roses", (neither of which I have read but intend to read). "We all bring our biases with us, and those who have not experienced something may well hold strong opinions about it and those may be based on stereotypes, prejudices, or illusions that actual experience undermines." This is particularly important when we think of the use of "our own objective reality" when serving as a juror in cases that have life and death consequences for suspected criminals.
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