Editorial: When metaphors become myths

by Geoff Hart (ghart@videotron.ca)

Previously published as: Hart, G. 2008. Editorial: When metaphors become myths. the Exchange 15(4): 2, 8–9.

We all know that metaphors can mislead, a phenomenon with its own name: "overextending a metaphor". The problem is that metaphors depend on certain assumptions, and when we no longer examine the assumptions, or perhaps no longer remember them, we're entering risky ground. My favorite example is the metaphor behind the trash can icon that appears on most modern computer desktops: In the original Macintosh computer, files placed in the trash were automatically deleted ("the trash was emptied") at the end of the day, which made perfect sense to corporate employees who had janitors do this for them every night. It made far less sense for home Macintosh users, whose trash got emptied only when they chose to empty it, usually when there was no more room for it to contain anything else. Because of the many files lost by home users who didn't share the designer's assumptions, the modern Macintosh and Windows trash cans are no longer automatically emptied. Examining the assumptions underlying the original metaphor revealed problems with the metaphor, and the designer subsequently developed a solution to protect those who didn't share those assumptions.

Because metaphors are an important tool for understanding and communicating science, it behooves us to understand their limitations. When we extend metaphors beyond their usefulness, they become myths—attempts to explain reality that no longer have any significant relationship to the truth they were once intended to convey.

From a scientific perspective, economics provides a useful example of metaphors gone bad—assuming you're willing to grant, for the sake of argument, the assumption that economics is a science. Consider the metaphor of economic growth. On the one hand, we have historically seen the enormous rise in prosperity that accompanies economic growth. On the other hand, we recognize (apparently unlike most economists) that resources are limited. (See, for instance, my previous editorial, Everything has limits.) No matter how efficient we get, the Earth is only so large, and we can never increase the volume of our planet. So what are the assumptions that underlie the metaphor that economic growth equals prosperity and what are their limitations? The biggest limitations is that most economists choose to ignore externalities (things that are considered side-effects because they are difficult or inconvenient to include in economic models) such as pollution and resource depletion. If we accept the assumption that both are externalities and can be safely ignored, the metaphor works well. But it biases our thinking in unfortunate ways. Consider, for example, that the antonym of growth is stagnation (a very pejorative term), not stability or equilibrium.

Ecologists have gradually begun persuading economists to turn this metaphor on its head by invoking the modern metaphor of sustainability. In this metaphor, we see a clear recognition of the limits on growth that are imposed by the capacity of nature to provide the necessary resources. The notion of sustainability is that growth is acceptable up to a point, but that subsequently, the system that is growing must reach an equilibrium, with the limits to growth defined by the ecosystem's carrying capacity. Forests, for example, grow rapidly until they reach a certain maximum size that is determined by the available resources (space, nutrients, light, etc.), but then become largely stable thereafter, though metastable is actually a better description. The problem this poses for growth is clear if we start to see the trees despite the forest: the ecosystem as a whole remains stable, which is a good thing, but because no further growth is possible without somehow increasing the available resources, this means that either no new trees can be recruited (an ecologically unrealistic condition) or that any new trees that arise must either replace existing trees or subsist on inadequate resources, remaining stunted and impoverished compared to the dominant trees. This raises an uncomfortable question: If we replace trees with humans, does sustainable growth remain an acceptable metaphor?

Please note that I have introduced these examples to illustrate the problems with both a metaphor and its counter-metaphor, not to propose explicit solutions. As the differences in the two metaphors show, reality is complex and not easily described in a way that prevents the metaphor from being overextended. Nonetheless, by comparing the assumptions of the two economic models (growth unconstrained by limitations on the available resources, and sustainability defined by eliminating growth), it may be possible for us to seek an appropriate middle ground: growth sufficient to match the needs of the growing human population, but constrained by a realistic assessment of how much growth the ecosystem can sustain without irreversible damage.

The importance of this essay to scientific communicators is that whenever we choose metaphor as a communication tool, we must carefully define our assumptions, identify the limitations of those assumptions, and communicate those limits to our audience. This is both ethical, and a necessary component of clear and successful communication. If we fail to perform this task, we transform something as useful as a metaphor into a myth that may mislead more than it informs.

My essays on scientific communication have now been collected in the following book:

Hart, G. 2011. Exchanges: 10 years of essays on scientific communication. Diaskeuasis Publishing, Pointe-Claire, Que. Printed version, 242 p.; eBook in PDF format, 327 p.