Like Clockwork

Light is a wave or a particle; the body’s cells have machinery; the brain is a computer and the genome is a code. All of these are metaphors – not just metaphors used by science writers to help lay people understand complex phenomena, but those used by the scientists themselves. Even in scientific papers – texts where one might least expect the use of figurative speech – metaphors abound. They are simply part of language and communication, and they play a role in scientific thinking as well.

One of the more common metaphors in biology is that of the clock. Rona Aviram and Gal Manella are research students in the chronobiology lab of Prof. Gad Asher of the Weizmann Institute of Science’s Biomolecular Sciences Department. Their research field is entirely based on the metaphor of a 24-hour self-winding clock ticking away in our bodies. These “biological clocks” are complex biochemical networks that operate in all our organs and regulate various physiological and behavioral circadian rhythms. Of course, there is no such ticking mechanism. Yet, one need only to peruse the explanations of the Nobel-winning studies by circadian rhythm researchers Jeffrey C. Hall, Michael Rosbash and Michael W. Young (Physiology or Medicine, 2017), to understand how pervasive the idea of a clock is today in the field. Aviram and Manella asked: How does a metaphor like a clock shape scientific research?

The clock metaphor over time

Aviram and Manella first engaged in some historical research to better understand how this mechanical metaphor had entered the science of biology. They found that in the 17^th century, ideas borrowed from mechanics had gripped the world of scientific enquiry – none more so than clockwork. Renes Descartes famously posited that the Universe and everything in it was a sort of clockwork, and humans a part of this predetermined, ticking machine. (Ironically, his idea of a clockmaker became a metaphor for pseudoscientific “intelligent design” as well.)

Yet it was only in the 1950s that the clock metaphor became a widespread term to describe daily rhythms in biology. Aviram and Manella were surprised to find that the use of the metaphor did not happen by chance. It was deliberate, with the consensus of leading researchers, and its use may even have contributed to the establishment of chronobiology as an independent research field.

But how does the use of a metaphor shape scientific thinking? The students undertook an analysis of the literature based on the idea proposed by two linguists, George Lakoff and Mark Johnson, of the conceptual metaphor. A conceptual metaphor arises when we not only apply the term linguistically, but we attribute the properties of one thing to something else altogether. (For example, if time is money, we assign it a financial value, saying someone is living on borrowed time or asking if something is worth the time.) By calling a biological occurrence a clock, we might phrase our research questions in terms of mechanisms and time-keeping.

Aviram and Manella indeed found the research questions, design of experiments and scientific literature rife with extensions of the clock metaphor. For example, studies searched for mechanisms to reset the biological clocks, or to take it apart to see what makes it tick. Looking at the system as a clock has led to hypotheses that are very unique and specific to clockworks. For example, biological systems tend to be temperature-sensitive, running faster when warmer and more sluggishly in the cold. But, if the body has an accurate clock, it might also have a mechanism for adjusting to changes in temperature: a correcting mechanism known as “temperature compensation” in metal-and-silicon timepieces. This line of reasoning led to a series of experiments that uncovered exactly such a mechanism.

The lifespan of a metaphor

Although the term clock is so embedded in the descriptions of this biological field as to seem self-evident, it was not the only metaphor in the running for the title. Some researchers in the 1940s called it a gramophone; others in the 1970s thought the phenomenon worked more like a tape recorder. Nowadays, some researchers have moved away from the mechanical metaphors, comparing it instead to an orchestra conductor.

“We adopt metaphors as shorthand for complex concepts or processes. It is part of the way we talk and think, and it becomes, intentionally or not, a part of our perspective, even in science,” says Manella. “Exchanging metaphors can renew a research field, even giving scientists a new perspective or helping them frame new questions,” says Aviram. 

To mix some metaphors, language is living – it changes as people speak it and write it; science is an ever-shifting trek into the unknown, and our metaphors, even those so thoroughly embedded as to give their name to an entire field of research, will shed their skins, go with the flow, and upgrade to the next generation.