The Problem with Digital Twins
Digital twins crack me up. Here’s why: it’s the origins of the word ‘digital’ and ‘twin’. As @Nick_Tune (not Nick Cage) pointed out, this language does matter now. It’ll be even more important, moving forward.
In the twentieth century, we don’t think twice. Something that’s ‘digital’ is something that’s not analogue. Digital means computerised, and that’s about the sum of it (binary joke, there). Ever since Konrad Zuse built the Z1, in 1938, we’ve lived in a digital world. Except…
Parchment precedes pixels. The truth is, people were saying ‘digital’ in 1838, 1738 – hell, even in 1438, ‘digital’ had a well-defined meaning. The earliest evidence of the word shows that is was used to denote ‘a whole number less than ten’ — because people counted, using their digits. (It has nothing to do with digitalis, although gloves… fingers… fairies… little folk’s fingers… folk’s… fox… foxgloves… it’s a well-known etymologist’s nightmare. I’ll move on.)
Analogue vs digital
Analogue devices used a continuous input – such as voltage – to compute a result, literally, by analogy: comparing one linear output with another. But post-Zuse machines used data that was represented as a series of digits. Numbers. At their most basic level usually, as in, ‘01010101’.
That series of digits gave rise to the term digital, and the OED confirmed it in 1989 with the definition, ‘of, pertaining to, or using digits; specifically applied to a computer that operates on data in the form of digital or similar discrete elements.’ Wow.
Now, though, digital has more widespread, generic significance: we’ve come to accept something as being digital if it’s in any way connected with production by computerised means. Eventually, we’ll stop using the term. It’s ‘analogue’ that will be revered as something special – anyone with an original, ticking, Mickey Mouse watch already knows this: analogue has never been mickey mouse.
In the meantime, digital has given birth to a new concept: the virtual counterpart of an object that exists in the real world. From driver-designed cars in a virtual showroom to race-car engines that never exist on a physical test-bench – and as buildings (buildings in particular) … we’re bringing a new world to life, in theory. But here’s the thing: some people refer to these constructs as ‘digital twins’, some take the BIM fork, and some guides – mentioning no names (Centre for Digital Built Britain) – such as the recently-published Gemini Principles, are adding new layers of complexity to the concept in a well-meaning effort to simplify matters, as regards a ‘true definition’.
A digital twin is a realistic interpretation of something physical: what distinguishes a digital twin from any other digital model is its connection to the physical twin.
Gemini vs twins
What ‘connection’. Why must we have the constraint, ‘realistic’. Which of these is a rhetorical question – and why is ‘Gemini’ such an interesting choice?
Digital is as digital does: that part of the puzzle was easy – a real peach of an explanation, in fact. And <ahem> I could eat a peach for hours, or so the saying goes. Twin should be specific enough, too. It’s derived from the thirteenth century Old English getwinn, or ‘double’, and, getwinnas was ’two born at one birth’. So it’s easy to see how the powers that be might have leapt to foregone conclusions, by choosing ‘Gemini’ for their principles. Gemini comes from the Latin, geminatus, ‘twinned, equal,’ as the past participle of geminare, meaning to double or repeat.
What’s ironic here, is that the constellation – Gemini – is the epitome of a misnomer that’s given rise to ‘gemini’ being thought of as ‘a twin’, the world over.
Castor (he who excels – being larger than the Sun, about two times its mass and nine times its radius) is the alpha star; Pollux (he who is quite sweet, no, I don’t know either) is the beta star. The so-called heavenly twin bodies aren’t twins at all. Leda was their mother, but the Dioscuri actually had different fathers (the Greeks were the inventors of dysfunctional families), so the boys were half-brothers – similar, but with different origins: just like the stars, on-screen or off.
I’m circumventing the point: in our search for an apposite definition, and while the Gemini Principles try to narrow it down for the time being, digital (in its original form), means fingers. Twin, we accept as meaning two. Bearing in mind how easy it is to misinterpret ‘victory’, even Castor Troy would have laughed at the symbolism, there.