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What are Ethos, Pathos, and Logos? How Researchers Can Use the Rhetorical Triangle 

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Okay, as a researcher, you’re familiar with how to write a journal article and the IMRAD structure of a research paper. But science communication isn’t always so straightforward. Rhetorical devices like ethos, pathos, and logos are not just for lay people or non-scientific communications. As a scientist, you might have to use more than just data to convince your audience. For example, when you’re writing a commentary or opinion piece, engaging in advocacy for science-based causes, or even making a speech to inform or educate a lay audience. Here’s where you can use the three key elements of the rhetorical triangle:  

  1. Ethos,  
  1. Pathos, and  
  1. Logos. 

What is Ethos? Building Trust as a Scientist  

Ethos is about credibility. Your audience should view you as a credible and reputed source, and trust in your knowledge and abilities. This sounds easy for a researcher, isn’t it? But in the Covid-19 pandemic, you must have witnessed a lot of pseudoscience on social media and mainstream media. As a consequence, lay audiences are increasingly aware that scientists are fallible—you can no longer simply say “Trust me, I’m a scientist.”  

Instead, present your qualifications, outline your experience, and frankly acknowledge if something is beyond the scope of your expertise (like if you’re a pediatrician but are asked a question about how specific genetic variants increase the risk of autism spectrum disorder).  

What is Logos? How Researchers Can Use Logos 

Logos refers to logic. Again, something quite easy for scientists to work with. After all, science is about logical inferences from data and analysis.  

You probably have amassed solid data and know how to interpret it. The trick is to make sure your audience can follow your logic. Be clear, use simple language, avoid jargon, and use visual or multimedia aids to make your arguments accessible to a wide range of people.  

What is Pathos? Using Emotion in Science Communication  

Pathos refers to using emotional appeal to convince your reader or listener. People don’t want to listen to robots. They want to connect with a human being. Pathos is the rhetorical element that helps you do that.  

Should scientists use pathos? Varpio (2018)‘s article in Perspectives in Medical Education gives some powerful examples of how pathos can be effectively used in science communication without undermining one’s credibility. As a scientist, you don’t need to be 100 percent impersonal. It helps to share some personal anecdotes, talk about your feelings and experiences, and if your audience can see you, smile and make eye contact. One of our sister platforms showed that even humor has a role in scientific discourse! 

Using Ethos, Pathos, and Logos: Examples 

Dr K is an ecologist who has been invited by an environmental group to conduct a session for the public on the need to conserve a local forest region. Dr K begins by talking about  

  • her years of experience in ecology and forest ecosystems,  
  • her award-winning research projects,  
  • her position at a prestigious national university, and  
  • the articles she has published in top-tier scientific journals.  

She gives clear examples of how protecting that local forest can improve the public’s quality of life. She draws a link between forest conservation and reduced need for chemical fertilizers and pesticides for local crops. She uses multimedia to illustrate how lack of forest cover can result in reduced precipitation and water scarcity.  

Throughout her talk, Dr K is warm and personable. She makes the audience laugh when she tells them how she got lost while doing fieldwork in the local forest and how monkeys absconded with her lunchbox. She portrays herself as a friend, not a patronizing expert.