• Samuel Brod

Are metaphors damaging your medical writing?

The use of metaphors to explain scientific concepts is a practice almost as old as science itself. But are these figures of speech a silver bullet or a wolf in sheep's clothing?

Metaphors are a vital tool in the kit of any science communicator. These rhetorical devices invite us to see a person, idea, or object differently by inviting comparison. In literature, the metaphor enhances meaning and feeling; in politics, it's a tactic to sway opinions; and for science, a fundamental method to aid understanding. However, metaphors do come with risks.

Metaphors are classically described as having two parts: the tenor, which is the subject to which attributes are ascribed, and the vehicle, which is the object whose attributes are being borrowed from.

For example:





is like

a ladder


are like


Black holes

are cosmic

vacuum cleaners

The body

is a


The price of using a metaphor is that it will transfer all of its vehicle's personal and cultural connotations to the tenor. This isn't an issue when the vehicle is simple, such as a 'ladder,' or a 'wire'. However, things get more tricky when you start employing more abstract terms such as 'battleground'.

Metaphors focusing on war and conflict are rife throughout science. While they can undoubtedly make a topic more engaging, evidence suggests their use is a double-edged sword. In one study, using battle metaphors to explain cancer treatment and prevention made patients less willing to enact healthy behaviours. The authors explain the damging effect of metaphors in this context:

"Battles and war are usually seen as being difficult. Indeed, reading about a person's 'battle' or 'fight' against cancer makes cancer treatment seem more difficult. One way to approach a battle is to surrender and give up control. Consistent with this implication, battle metaphors increase fatalistic beliefs about cancer prevention.”

A further study investigating militaristic metaphors used by governments to draw attention to the risks of COVID-19 found it had the unintended consequence of causing people to ascribe greater responsibility (and assumedly blame) to their governments in managing the pandemic and less individual responsibility to themselves.

Using a vehicle that describes human attributes can also be problematic. Take Richard Dawkins' 'Selfish Gene' – a powerful metaphor (which Dawkins now regrets choosing) that paints evolution as harsh, competitive, and sometimes cruel. Like many scientific metaphors, Dawkins has tied a natural process to human behaviour and all the cultural and psychological baggage that comes with it. In doing so, he may have put some people off the idea of natural selection and perhaps even science in general.

The meaning of a 'commonplace' vehicle may also differ or be entirely unheard of across different cultures, classes, and genders. For example, medical metaphors created with fair-skinned populations in mind, such as the 'peaches and cream' complexion of hypothyroidism or the 'bulls-eye rash' of Lyme disease risk confusing or, worse, alienating patients with darker skin.

That said, science is inescapably rooted in metaphor, and scientific communication depends on these figures of speech to help make the abstract concrete or add some spice to a bland fact or figure. However, in pursuit of a striking metaphor, a writer can risk going against the key objectives of their copy; clarity and accessibility.

When using or creating a metaphor to help explain a scientific concept, consider how 'commonplace' the vehicle you chose might be and how open it is to multiple interpretations. Investigate whether the effectiveness of your metaphor is grounded on firm evidence. And if you are genuinely in doubt, don't guild the lilly. Skip the metaphor entirely and focus on writing a plain description couched in simple terms.