Our perception of 'analog' and 'digital' in the natural world

The words 'analog' and 'digital' sound rather precise. About a century ago, introspective engineers were inspired by these basic notions to create operational definitions and analytical tools that make use of these two labels. These can still be useful -- not so much in the natural sciences, as I'll explain below, but occasionally for setting goals in an engineering workplace. But these historic and highly-constrained technical terms are something of a distraction for any serious investigation into the human nature of 'analog' and 'digital'. The key to approaching these notions is to remember that 'analog' and 'digital' are ideas, brain-internal entities, universally available to normal human cognition. Like all ideas, they recruit mental faculties that interact in complex, unknown ways. The ways they interact in the brain seem, in this case, to tend towards mutual exclusion.

When the idea of 'digital mechanism' is associated with something in the world, it always entails an understanding that this 'mechanism' exists within an 'analog world'. It reacts in a not-quite-sufficiently-concomitant fashion, evidence for which is representable by discontinuous functions -- in other words, the 'digital' system reacts with 'unusual prominence' after some 'threshold' has been reached. Of course, anything in the natural world can be found to have this 'character', and often human investigators are very keen to determine the expression and causation underlying a subject's 'digital' character. 

At the same time, the same subject of investigation will reveal 'analog' characteristics -- again, when the investigator looks for them. Unfortunately, this is true of perhaps the entire range of human-observed properties of complex systems: something that is 'whole' also seems to have more-or-less 'distinct' 'parts', something that 'acts' also seems to be 'passive', something that 'flows' also appears to be 'static' ... and special training is typically required to regularly resolve these apparent contradictions when taking different conceptual-perceptual approaches. 

One could characterize 'analog' and 'digital' as 'projections' of human cognition upon our limited sensations of the world around us, real and imaginary -- the same cognition and sensation that makes us feel that we know 'the world'. When we call something 'analog' and 'digital', we're mostly looking at ourselves, using mental equipment that, when genetically intact, required stimulation during development to prevent atrophy. 'Analog' and 'digital' are universal, in the sense that, at the least, all humans can conceive of them. They are our biological inheritance.

We can test this by observing the world. What are simple examples of something in nature that is both analog and digital?  We observe a system that's near its tipping point -- such as a stick precariously perched on its end, on a fence, in the wind -- the 'analog' gradual movement will reach a threshold, and then 'the system', something which we define as observers, will achieve its 'next digital state'. 

Another example is a 'loaded' system -- using a slingshot, pull a rock back until it is also in a precarious state, then let go, which is a gradual 'analog' thing from one perspective, but could be seen as a 'digital switch' from another perspective, in which the rock 'discretely' moves from the state of being 'in the slingshot' to being 'out of the slingshot'. Any system, since it is observed by a human, has these properties, but we shouldn't despair -- although these properties appear together, one will typically dominate at one point, and another at another point, and sometimes the simultaneous perspectives are very easy to separate and identify. That is, one perspective can help us to construct a more enlightening analysis than the other ... although these are interdependent properties, so we can't ever totally discount one.

Since this is an epistemological issue, where the culprit is always human cognition, this 'finding what is important for a particular perspective' is possible even of complex affairs, far beyond the edge of what would be considered appropriate research subjects for the natural sciences. The other day, talking to someone who studies urban policy, I pointed out that a well-known government program, 'Urban Renewal', was very destructive of people's lives and neighborhoods. I gave one example, where a proposed $200 million Urban Renewal expense would have destroyed an entire neighborhood. He agreed, but then pointed out that the urban renewal fund had made one investment that was quite good. I agreed, but pointed out that this was a $2 million investment. We were both making correct points about the fund, but the massive downside of the large investment vastly outweighed the upside of the small investment, meaning we could say 'Urban Renewal' is a bad idea, by precisely two orders of magnitude.

That said, if one was studying projects that made a small number of people wealthy, with no concern for anything else, then clearly Urban Renewal would be 'good' in this sense. There are certainly people who make such assumptions.

Likewise, some natural systems have a 'digital' aspect that is far more prominent than its 'analog' aspect, given the interests of the researcher. In other cases, analog systems are more prominent. But the the key is to define 'prominent': prominent by which criteria of interest? It is possible to get 'out of our skins' a little better, and examine our interests.

In the natural science, 'most prominent' is 'that effect or aspect without which nothing would happen'. Again, there are multiple factors, and we bring multiple interests to the table, but we can examine these. 'Relative importance' or 'requiredness' or even 'essence' is often considered a mysterious idea. But not if we willingly examine ourselves, as part of our research. In the sciences, we need to continually re-examine our dogmas, judgments, and criteria for intelligibility, when considering what is 'important' in any investigation. And, in the case of internal, instinctive notions like 'analog' and 'digital', we need to try to recognize when our instincts are getting in the way, as they usually do, of further enlightenment regarding the world outside, and inside, ourselves.