Rules of Evidence: File Under Knowledge of Conventions

Just as discourse communities share conventions of genre, voice, tone, diction, etc., each has its own ideas about what kind and amount of evidence justifies a conclusion. Think, for instance, of what it takes to prove to a woman's support group and a court of law that a husband has committed adultery. You need to discover the rules of evidence for any discourse community you wish to join. Why? Logos and ethos based arguments heavily depend on evidence to support them. If you don't use enough evidence or don't employ the right type, then the credibility of your arguments suffers or, in the worse case, might be destroyed.

Academic discourse has fairly rigorous standards of evidence, because the outside community often bases their opinion and actions on the knowledge we create and propagate. As a student, you might find these rigorous standards finicky, but you want your doctors to know what is enough evidence to decide what your disease is and not make mistakes. You want engineers to know (and not just think or believe) that the steel and concrete used to make a bridge is up to the daily load of traffic over it. In other words, you don't want folks making critical decision to have slack rules of evidence.

Part of developing an academic voice is learning what rules of evidence, that is what types and amount, are sufficient for the discipline you are studying to draw a conclusion. Those of us in English might be able to construct Shakespeare's life from the scant pieces of evidence on which we have to draw, but you don't want folks using these same rules to convict you of murder.

Here are some words we use to describe and talk about evidence. Learn them:

• opinion
• hearsay
• authenticity
• physical evidence
• relevance
• germane
• authentic
• expert
• sufficient
• enough
• lack of
• sufficiency
• eye-witness
• primary
• secondary
• biased
• source of
• documented
• refereed
• long standing
• degree of certainty
• smoking gun
• circumstantial
  
• empirical
  
• qualitative
• verifiable
• quantified