Monday, 15 November 2021

The Limits of the ‘Unknowable’

In this image, the indeterminacy principle is here about the initial state of a particle. The colour (white, blue, green) indicates the phase, that is the position and direction of motion, of the particle. The position is initially determined with high precision, but the momentum is not. 

By Keith Tidman


We’re used to talking about the known and unknown. But rarely do we talk about the unknowable, which is a very different thing. The unknowable can make us uncomfortable, yet, the shadow of unknowability stretches across all disciplines, from the natural sciences to history and philosophy, as people encounter limits of their individual fields in the course of research. For this reason, unknowability invites a closer look.


Over the many years there has been a noteworthy shift. What I mean is this: Human intellectual endeavour has been steadily turning academic disciplines from the islands they had increasingly become over the centuries back into continents of shared interests, where specialized knowledge flows over one another’s boundaries in recognition of the interconnectedness of ideas and understanding of reality.


The result is fewer margins and gaps separating the assorted sciences and humanities. Interdependence has been regaining respectability. What we know benefits from these commonalities and this collaboration, allowing knowledge to profit: to expand and evolve across disciplines’ dimensions. And yet, despite this growing matrix of knowledge, unknowables still persist.


Consider some examples.


Forecasts of future outcomes characteristically fall into the unknowable, with outcomes often different from predictions. Such forecasts range widely, from the weather to political contests, economic conditions, vagaries of language, technology inventions, stock prices, occurrence of accidents, human behaviour, moment of death, demographics, wars and revolutions, roulette wheels, human development, and artificial intelligence, among many others. The longer the reach of a forecast, often the more unknowable the outcome. The ‘now’ and the short term come with improved certainty, but still not absolute. Reasons for many predictions’ dubiousness may include the following.


First, the initial conditions may be too many and indeterminate to acquire a coherent, comprehensive picture of starting points. 

Second, the untold, opaquely diverging and converging paths along which initial conditions travel may overwhelm: too many to trace. 

Third, how forces jostle those pathways in both subtle and large ways are impossible to model and take account of with precision and confidence. 

Fourth, chaos and complexity — along with volatility, temperamentality, and imperceptibly tiny fluctuations — may make deep understanding impossible to attain.


Ethics is another domain where unknowability persists. The subjectivity of societies’ norms, values, standards, and belief systems — derived from a society’s history, culture, language, traditions, lore, and religions, where change provides a backdraft to ‘moral truths’ — leaves objective ethics outside the realm of what is knowable. Contingencies and indefiniteness can interfere with moral decision-making. Accordingly, no matter how rational and informed individuals might be, there will remain unsettled moral disagreements.

On the level of being, why there is something rather than nothing is similarly unknowable. In principle,  ‘nothingness’ is just as possible as ‘something’, but for some unknown reason apart from the unlikelihood of spontaneous manifestation, ‘something’ demonstrably prevailed over its absence. Conspicuously, ‘nothingness’ would preclude the initial conditions required for ‘something’ to emerge from it. However, we and the universe of course exist; in its fine-tuned balance, the model of being is not just thinkable, it discernibly works. Yet, the reason why ‘something’ won out over ‘nothingness’ is not just unknown, it’s unknowable.


Anthropology arguably offers a narrower instance of unknowability, concerning our understanding of early hominids. The inevitable skimpiness of evidence and of fine-grained confirmatory records  compounded by uncertain interpretations stemming from the paucity of physical remains, and of their unvalidated connections and meaning in pre-historical context  suggests that the big picture of our more-distant predecessors will remain incomplete. A case of epistemic limits.

Another important instance of unknowability comes out of physics. The Heisenberg uncertainty principle, at the foundation of quantum mechanics, famously tells us that the more precisely we know about a subatomic particle’s position, the less we know about its momentum, and vice versa. There is a fundamental limit, therefore, to what one can know about a quantum system.


To be clear, though, seemingly intractable intellectual problems may not ultimately be insoluble, that is, they need not join the ranks of the unknowable. There’s an important distinction. Let me briefly suggest three examples.


The first is ‘dark energy and dark matter’, which together compose 95% of the universe. Remarkably, the tiny 5% left over constitutes the entire visible contents of the universe! Science is attempting to learn what dark energy and dark matter are, despite their prevalence compared with observable matter. The direct effects of dark energy and dark matter, such as on the universes known accelerating expansion, offer a glimpse. Someday, investigators will understand them; they are not unknowable.


Second is Fermat’s ‘last theorem’, the one that he teed up in the seventeenth century as a note in the margin of his copy of an ancient Greek text. He explained, to the dismay of generations of mathematicians, that the page’s margin was ‘too small to contain’ the proof. Fermat did suggest, however, that the proof is short and elegant. Four centuries passed before a twentieth-century British mathematician solved the theorem. The proof, shown to be long, turned out not to be unknowable as some had speculated, just terribly difficult.


A last instance that I’ll offer involves our understanding of consciousness. For millennia, we’ve been spellbound by the attributes that define our experience as persons, holding that ‘consciousness’ is the vital glue of mind and identity. Yet, a decisive explanation of consciousness, despite earnest attempts, has continued to elude us through the ages. Inventive hypotheses have abounded, though remained unsettled. Maybe thats not surprising, in light of the human brain’s physiological and functional complexity.


But as the investigative tools that neuroscientists and philosophers of the mind yield in the course of collaboration become more powerful in dissecting the layers of the brain and mind, consciousness will probably yield its secrets. Such as why and how, through the physical processes of the brain, we have very personalised experiences. It’s likely that one day we will get a sounder handle on what makes us, us. Difficult, yes; unknowable, no.


Even as we might take some satisfaction in what we know and anticipate knowing, we are at the same time humbled by two epistemic factors. First is that much of what we presume to know will turn out wrong or at most partial right, subject to revised models of reality. But the second humbling factor is a paradox: that the full extent of what is unknowable is itself unknowable.



Thomas Scarborough said...

Perhaps it is worth distinguishing between science and its outcomes. Cosmologist John Barrow wrote, “It is one thing to know the laws of Nature, but quite another to know the outcomes of those laws.” In this case, the outcomes of scientific theory are by and large unknowable.

I'm not sure that many would agree with your judgement that 'human intellectual endeavour has been steadily turning academic disciplines ... back into continents of shared interests'. Computer scientist Pedro Domingos writes, 'Science today is thoroughly balkanized.'

A question for the author: What would be our appropriate response to unknowability?

Keith said...

I disagree, Thomas, with the Pedro Domingos quote you cite, that ‘Science today is thoroughly balkanized’. There are many examples in science that push back against that observation; here, I’ll offer just one: neuroscience. The field of neuroscience is considered highly interdisciplinary, to encompass biology, chemistry, physics, mathematics, medicine, physiology, computer sciences, engineering, and, yes, philosophy (notions of consciousness, mind, free will, identity) and ethics. Hardly ‘balkanisation’, I propose.

Keith said...

The question ‘What would be our appropriate response to unknowability?’ seems, Thomas, to presuppose there is a response that might somehow remedy unknowability. But, by definition there surely is no such panacea, beyond our continuing defiantly to discover as much as possible about what’s knowable, while tirelessly pondering the unknowable. Hanna Arendt said it best, perhaps: ‘I believe it is very likely that men, if they ever should lose their ability to wonder and thus cease to ask unanswerable questions, also will lose the faculty of asking the answerable questions upon which every civilization is based’. Maybe Arendt’s nostrum is the most ‘appropriate response to unknowability’.

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