Reasoning involves making arguments.
Textbooks and websites often divide communication into separate types, such as "Narrative," "Descriptive," "Analytical" or "Argumentative" (e.g. Purdue OWL). Some books present as many as 8 or even more categories of communication (Schnorenberg, 2013).
However, in a practical sense, it is very difficult to communicate without making arguments (Erduran et al., 2004). We always communicate based on a particular set of assumptions and values. Moreover, successful communication involves transferring information to someone else, which changes their thinking or perspective (Day and Gastel, 2011). Therefore, communication involves changing someone's thinking to accept new information predicated on our assumptions and values (which is a reasonable definition for making a persuasive argument; Mirriam Webster Dictionary).
For example, narrative communication is often structured around themes or objectives for readers to take from a story. Although narrative communication may employ a framework that does not seem persuasive (like a chronology), the author nonetheless selects a story, story structure, and wording to support a theme or objective. The process of selection can be seen as an implicit argument for the the theme. Similarly, although the content of descriptive essays may seem objective, the author still makes many decisions about what information to include and what information to exclude. Deciding what to include in a description is an implicit argument, often for the importance of some pieces of information over others. Because of stringent word count requirements, reporting scientific research very often involves making choices about what information to include and to exclude. Moreover, it is difficult or impossible to make purely objective word choices in many contexts, resulting in implicit arguments (Ross et al., 2017). Therefore, many types of communication involve implicit or explicit arguments with the objective of changing thinking in a desired way.
If we accept the premise that much communication (including scientific communication) is fundamentally argumentative, we can move on to the question: How can we make effective arguments?
Over 2,000 years ago, Aristotle proposed three basic strategies for making compelling arguments (i.e. "Rhetoric;" Aristotle, ~350 BCE):
ETHOS, supporting the credibility of the author,
PATHOS, appealing to the feelings or intuition of the audience, and
LOGOS, basing the argument on reason.
Scientific communication involves all three strategies: Ethos, Pathos, and Logos.
However, scientists do NOT consider arguments based on Ethos and Pathos to be strong.
Although establishing a baseline of credibility is important, scientists do NOT accept arguments based solely on the authority or status of a researcher (which is why you should critically question every recommendation in this module). Moreover, scientists also try NOT to make decisions influenced by feelings or intuition. Although feelings and intuition can be useful for creating hypotheses, intuition can lead to decisions that reflect heuristic short-cuts instead of strong inference (Tversky and Kahnemann, 1974). Moreover, informal arguments that use Ethos and Pathos can also be complicated by a number of rhetorical tricks that persuade without robust evidence.
Therefore, although Ethos and Pathos ARE a part of scientific communication, their use is usually very limited and subtle. Scientific arguments cannot be based primarily on Ethos or Pathos.
Scientists construct arguments that are not only persuasive, but also truth seeking (Ramage et al., 2016). Therefore, scientists seek to base decisions on REASONED frameworks (Logos) to the extent possible. Using effective reasoned frameworks is essential for making scientific arguments.