I was working on a paper recently, and my boss included a editing note that got me thinking.  The topic dealt with certain circuits in the limbic network of the brain.  The note included the line: "limbic connections are very complex".   The point of the edit was to emphasize that problems in the limbic network (like seizures) are difficult to treat in part because every part of the network is connected to every other part.  Therefore, it's hard to pin down any one effect that one part has on another. 

The essence of the edit is accurate.  The limbic network, like any other system of neural circuits, is complex.  It is an apt word: millions of neurons, trillions of synapses, microscopic electrochemical events happening in four dimensions.  The word is also apt for certain computer networks, ecosystems, weather patterns, global politics and economics.  In fact, the more you think about it, the more it comes up in all the really interesting- and, not by accident, prospering- research fields.

The word "complexity" has enjoyed a lot of popularity particularly in the last thirty years.  It is the beneficiary of a movement in both research and popular consciousness.  It is co-popular with other words, such as "turbulent," "fractal," "emergent" and "non-linear".  Although these words clearly differ from each other in definition and in context, their usage has been steadily increasing because of the mystique that they acquired.

Nowadays, labeling a subject as complex has two distinct advantages: first, it implies that study of the subject requires very elaborate, enlightened, sophisticated, (well-funded) methodologies, and second, it implies that the researcher is capable of such methodologies, and is therefore one smart cookie.  It adds credence and gravitas.  There are not one but at least two journals that deal specifically with complexity, not counting Science Signaling or other journals whose topics are universally considered complex.  It calls to mind visions of chalkboards of mathematical equations and inscrutable diagrams that look like a game of Cat's Cradle gone horribly wrong. The word may have the added bonus of keeping people from looking to closely at the research, for "complex" also means "hard to understand in only five minutes" and can cause nausea to those addicted to the Information Age.

The physicist Richard Feynman, when he was getting the Nobel Prize, became annoyed when reporters kept asking him to summarize his findings in brief snippets (before the blog era!).  Afterwords, the cab driver, who had overheard the interview, said "if you could explain it in five minutes, it wouldn't be worth a Nobel Prize".  Some people really are smart cookies. 

But the magic of complexity may be waning.  Not that systems are getting any simpler.  The value of the word rose as the technology to study complex systems became refined, and opened doors to studying phenomenon that only a few decades before were far beyond our grasp.  The era made complexity feel like a new and exciting thing, something that opened doors of knowledge.  But the technology has been around for a while now.  Excitement is fleeting.  The lull has made us realize a stark truth: we don't really need science to tell us that something is complex. 

In fact, the word may be reaching a state of being that is uncomfortable for any word: an effective cliche.  Welcome to Webster's limbo.

So the next time that you're doing a presentation on a system with a quizillion parts, and your instinct is to illuminate the audience with the fact that your system is complex, stop to consider if they already know.  Save the brilliant luster for the elegant and novel findings.  It's that simple.