Stop Saying Dynamical

noDynamical

Following close behind experimental testing of falsifiable hypotheses, the secondary responsibility of a scientist is arguably clear communication of results. Given that the majority of research is ultimately funded by the tax-paying public, it is important that outcomes are eventually conveyed in a manner that can be understood by an intelligent layperson. Increased scientific literacy in policy makers and their constituents is a prerequisite to face modern challenges such as changing climate, public health, and the consequences of population pressure. Effective outreach to the public is more important than ever. Accepting the previous statement, why is there a continuing trend among scientists to mask communicative content through cryptic language, particularly when perfectly acceptable and widely recognized terms are available? I’ll focus on what I consider to be the most obvious and ridiculous offender, the great scourge of scientific writing, faculty information pages, and grant proposals; the great occluder of meaning, intimidator of readers, the entirely redundant bit of lexicon: dynamical.

Dynamical, like its more accessible and less attention-hungry sibling word dynamic, has its roots in the Greek dynamikos, meaning powerful. In general both terms relate to something that changes with time. Since both “dynamical” and “dynamic” function as adjectives, they are essentially interchangeable, the only difference between that I have ever been able to discern is the demographics of their use. “Dynamical” is used by physicists, mathematicians and engineers who work in dynamical systems theory, a branch of mathematics dealing with systems described by differential (if continuous) or difference (if discrete) equations. The additional suffix “-al” that delineates the two words seems to have been born of single, somewhat malicious intent: to serve as brick and mortar in the construction of an ivory tower separating scientists and small-folk. It is exactly this sort of word choice that leads to the perception that scientists have more smarts than sense and that they produce results that ultimately fail to have any application to the real world. Ultimately this serves as fuel for the anti-science fire burning through the minds of policy makers and the public. Consider the following two sentences and the impression they would leave on a reader over a morning coffee:

“We utilize the time-slice method as a means of dynamical downscaling to specify expected climate change for Southern Europe”

“We utilize the time-slice method as a means of dynamic downscaling to specify expected climate change for Southern Europe”

From:

U. Cubaschll, H. von Storch, J. waszkewitz, E. zorita. Estimates of climate change in Southern Europe derived from dynamical climate model output . Climate Research . November 29 , 1996.

Even though the sentence makes reference to specific methods that a non-specialist reader might not be familiar with, the language is descriptive enough to impart a conceptual understanding of what the authors describe, except for that cumbersome “dynamical,” which throws the whole thing into question. It reads as if it came from a humour piece poking fun at absent-minded professor types. The null-meaning suffix implies there is meaning above and beyond the root word where there is none, it just sounds more complicated. This is not an outcome that scientists should strive for, no matter how intelligent it makes them feel to use it.

As disciplines in life science become increasingly concerned with complexity and modeling, I expect the number of life scientists interested in studying dynamic systems will only continue to rise. Given the particularly relevant nature of life sciences to understanding our relationship to our living planet, I beg you, wherever possible, to avoid using the word dynamical. The physicists, mathematicians, and engineers may be entrenched in their devotion to the nonsense word, but there’s no reason for this senseless departure from clarity to infect biologists, ecologists, biochemists, etc. any more than it already has. The arbitrary and counterintuitive way that scientists name the genes they discover-a combination of sarcasm, mystery and the opposite of their function-is a big enough mess.

 

Consider this an invitation to attempt to delineate the dynamic/dynamical word pair in the comments.

Stereographic anaglyph from shift-lens

In thinking about camera arrays, integral photography, and light fields, I began to see the similarities between stereographic photos and those from an array of cameras (or a single camera occupying multiple positions at different times). What sort of depth can be achieved by a moving lens over a stationary sensor? A fair amount, for distances at which the object distance is not >> than the inter-aperture distance between lens positions. The result is below: you’ll need a red/blue pair of filters or glasses to view it. Tilt-(shift) stereograph

A perspective control lens like the one used here is typically used to straighten the “vanishing lines” of tall buildings or features without wasting sensor/film space, and generally for perspective control. The lens I used here was a 35mm f/2.8 Canon FD tilt-shift lens on a Nikon D5100 with a Fotodiox mount/infinity correction adapter, the images were separated by ten lateral ticks as marked on the lens body (these appear to be about a millimetre, but are not labeled). The object distance was approximately ten cm.

Plenoptic imaging on a macro bellows rail

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After watching Dr. Marc Levoy’s talk on light fields and the Stanford camera array I thought I’d investigate for myself the uses for synthetic aperture photography. From the talk:

By changing the amount of shift, you can change the depth of objects that are in focus. And here’s what that looks like. So we’re focusing synthetically on the bushes, across the street through my grad students into the building and there’s a step stool in the building.

This is about the same as matching up the left/right channel on a stereo anaglyph, but with more perspectives as inputs. To get a feel for things I drilled out a camera mount to attach to the end of a macro bellows rail and took a series of horizontally displaced images, shifting and combining them in Octave to focus at different depths.
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