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Feb09

The Siren Songs of Systems Engineering

by zscott

The Siren, Edward Armitage, 1888

First you will come to the Sirens who enchant all who come near them. If anyone unwarily draws in too close and hears the singing of the Sirens, his wife and children will never welcome him home again . . . There is a great heap of dead men's bones lying all around . . . Therefore pass these Sirens by, and stop your men's ears with wax that none of them may hear . . . 

Homer, The Odyssey, Book XII

Zane Scott, Vitech Vice President of Professional Services

Most of us are familiar with Homer’s epic work, The Odyssey.  It tells the story of Odysseus’ 10-year journey home to Ithaca from the Trojan War. Along the way, he encounters many adventures and at one point is warned by the sorceress, Circe, of an impending danger – the song of the Sirens. Circe tells Odysseus of the Sirens whose beauty, musical talent, and songs lead sailors to their death along the rocky shores of their islands. She advises him to fill the ears of his men with beeswax so that they will not be tempted off course by the singing.

Odysseus does as instructed but lashes himself to the mast so that he can hear their song while remaining powerless to turn his ships toward it. This highlights an often overlooked but important point – both for Homer’s plot and our appropriation of it as an illustration. Even those who know the story generally operate with the assumption that the Sirens’ charms turns on the beauty of their countenances and/or their melody.

But a closer reading of Homer reveals otherwise. In Homer’s narrative, the Sirens sing to Odysseus “no one else has ever sailed past this place in his black ship until he has listened to the honey-sweet voice that issues from our lips; then goes on, well-pleased, knowing more than ever he did; for we know everything . . .” The lure of their song is not its beauty (or theirs) but its promise to impart exceptional wisdom.

This is the sense in which the postmodern-day Odysseus, the systems engineer, encounters the siren songs of our world. It is not the beauty of the Sirens or their songs that threaten the journey, but rather it is the emptiness of their promises of knowledge.

As we attempt to help systems engineering teams in both public and private sectors, we see them too often fall to the siren songs promising knowledge and truth from impossibly rocky shores. Two of these songs stand out with their Siren-like promises of wisdom hiding destructive results obscured by the songs.  

First Siren

The first Siren of the systems engineering journey sings the song of disintegration. In Homer’s poem, Odysseus’ major task is to successfully lead his men across a perilous course to safe harbor on the island of Ithaca, their home. Being drawn to their destruction on the rocky shores by the promise of greater knowledge would defeat that purpose.

The task of the systems engineer is to make a reliable prediction concerning the results that will be delivered by a system to such a degree that the designers can have a reasonable level of confidence that those results will fulfill the purpose for which the system is being designed. 

It is fundamental to the concept of systems that the results of any given system emerge from the way in which the system elements are related to each other. This is implicit in the definition of a system as a construct or collection of different elements yielding results not possible for the elements alone. The construct or collection provides the relationships among and between the elements. The results emerge from the elements related to each other in just those ways. Therefore, if we want to understand a system, we need to be able to see its elements – all of them – in relationship to each other as defined by the construct. We have to see the elements and the construct together as an integrated whole.

But in this case, the Siren would have us believe that we can see some of the elements (e.g. the requirements) in isolation from the others (say physical components) without losing insight into the nature of the system and its emergent results. Disintegration is okay (or even a virtue), the Siren sings, advocating the elevation of one aspect over another.

But, like the wise Odysseus, we should heed the call to stop our ears against this claim and sail past the rocky shores of the disintegration Siren and instead remain focused on the rewards of insight that flow from an integrated view of our systems.

Second Siren

The second Siren sings of misplaced standards. The folly of her song lies in the confusion it creates. Standards, in and of themselves, have intrinsic value. They provide a means to think and communicate about models in ways that are recognizable to others (who we presume will adopt those same standards).

But the second Siren encourages us to think that adopting a communication standard is the equivalent of adopting a method of constructing the model. This is the outgrowth of a deep-seated misunderstanding of the nature of communication and language. All communication begins with a model.

If I say “horse,” the word springs from a mental model of the animal. I might also draw a picture of my “horse.” The picture isn’t a horse or even a model of a horse, but it shows a subset of information about my model (four legs, tail, mane, etc.) The point here is that the picture (or view) came from my model. I defined what I wanted to communicate and drew the view to do that.

This is what happens with representational standards. Those who understand and adopt the standards get views of models. For others the views may be more difficult to interpret.

 

Systems engineers have a wide variety of stakeholders and others with whom to communicate. While communication standards may make sense in a subset of that community, others may be uncomfortable with communication taking an unfamiliar or misunderstood format.

But there is a bigger problem here. The second Siren song – misplaced standards – might tempt some onto the rocks of the first Siren: disintegration. In the quest for standards, they might be tempted to sacrifice the ability to create an integrated model in favor of a rigid adherence to the rules of the representational standard. “Is your methodology/tool conformant with the rules of the communication standard?” can be allowed to supplant the more important, “Will your methodology/tool allow me to create an integrated model that lets me make the necessary judgments about my design?”

Safe Sailing!

Like Odysseus’ sailors in Homer’s epic, we must stop our ears against the Siren songs along our journey. We cannot navigate by their promises. Whatever merit there might be in their lyrics, we should consider from the safety of home ports and not as a possible course of action on our way. Their promises of immediate wisdom are tempting but empty.

 

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Categories: MBSE | Misc

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