Evidence

Evidence

Definition: Information, facts, or material presented to support an assertion, claim, or argument. Used to establish truth and falsehood in various disciplines, environments, and contexts and is the basis of the scientific method. In the absence of clear facts and distinct understanding, evidence is used to establish the probability or likelihood of truth in a given situation. 

• Format: physical objects, circumstantial conditions, documents, testimony, digital data, observations, and more.

• Types: statistical, testimonial, examples, analogical, anecdotal, quotations, historical, logical, and visual

  • Examples: Evidence is used in legal proceedings, academic research, the scientific method, product evaluations, medical diagnoses, livestock valuations, music theory, weather forecasting, ethical judgments, sexual attraction, and everyday decision-making.

Categories of Evidence

Rhetorical evidence is divided into two basic categories: Primary and Secondary

• Primary evidence consists of information directly collected about the topic, often through observation, interviews, experiments, or surveys; it may also include firsthand reports from newspapers about an event.

• Secondary evidence, on the other hand, involves interpretations of primary sources, found in scholarly articles, newspaper analyses, and op-ed columns that offer specific perspectives or analyses of the event or topic.

Direct vs. Circumstantial

When building an argument, both direct evidence and circumstantial evidence may be used to support your claims. Each plays a unique role in establishing facts and supporting conclusions.

• Direct Evidence: Undeniable evidence that directly proves or supports a conclusion. Direct evidence provides a direct link to the occurrence, such as an eyewitness account.

  • • Example: A security camera recording that clearly shows a person breaking into a store. The video directly shows the action taking place, leaving no need for interpretation or inference.

• Circumstantial Evidence: Indirect evidence that suggests a fact or event without directly proving it. Rather than providing a direct link to the occurrence (such as an eyewitness account), circumstantial evidence relies on an inference or interpretation to connect it to a conclusion.

  • • Example: In a debate about media bias, a speaker might point to the fact that a particular news outlet consistently covers stories in a way that favors one political party. While this doesn't directly prove that the outlet is intentionally biased, it suggests a pattern of favoritism, which—when combined with other examples—could help build an argument for the presence of bias in their reporting.

Quantitative vs. Qualitative Data

Both types of data are valuable in research, often complementing each other—quantitative data provides the "what" in clear, measurable terms, while qualitative data offers insight into the "why" and "how" behind those numbers.

• Quantitative Data: This refers to numerical data that can be measured and quantified. It focuses on quantities, amounts, and measurable variables, and it often answers questions like "how many?" or "how much?" Quantitative data is often used to identify patterns, make statistical analyses, and draw conclusions based on measurable evidence.

  • • Example: The number of students enrolled in a class, the percentage increase in sales over a quarter, or the average temperature in a city.

• Qualitative Data: This refers to descriptive and non-numerical data. It focuses on qualities, characteristics, and the subjective interpretation of experiences or observations. Qualitative data often answers questions like "why?" or "how?" and is used to explore complex, deeper issues that can't easily be quantified.

  • • Example: Responses from interview participants about their experiences, open-ended survey answers, or the emotional tone in a written narrative.

Evaluating Evidence 

In general, all evidence can be evaluated based on three key criteria:

1. Sufficiency: The evidence should be ample. The more complex or controversial your argument, the more your audience will expect to see that you’ve thoroughly researched the topic and considered multiple perspectives, including counterarguments. Additionally, your evidence should come from sources that do not have a vested interest in the outcome of your argument.

2. Relevance: During your research, you may come across information that is interesting or important, but it must directly support the main point of your argument and be accepted by your audience to be useful.

3. Accuracy: Your evidence should come from reliable, well-informed sources that are best equipped to provide accurate and trustworthy information.

Rhetorical Evidence

Used to support arguments and persuade audiences. Rhetorical evidence is most often employed when a communicator's goal is to persuade an audience to think, feel, believe, or act a certain way. 

• The choice and effectiveness of rhetorical evidence depends on audience characteristics, persuasive purpose, speaker credibility, social and historical context, and the presentation's topic, structure, and content delivery.

• Primary types of rhetorical evidence include statistical, anecdotal, analogical, testimonial, historical, textual, logical, empirical, visual, and analogical.

Types of Rhetorical Evidence

1. Facts & Statistics

Objective data that can be verified and used to strengthen an argument.

1. • • • Example: "According to the CDC, smoking causes 480,000 deaths annually in the U.S."

2. Expert Testimony

Quotations or paraphrased statements from authoritative sources in a given field.

2. • • • Example: Citing a climate scientist when discussing global warming.

3. Examples

Specific cases or instances that illustrate a larger point.

3. • • • Example: Using a historical event to demonstrate a recurring social issue.

4. Analogies & Comparisons

Drawing parallels between similar situations to clarify a point or make an argument relatable.

4. • • • Example: Comparing the rise of renewable energy today to the industrial revolution in the past.

5. Anecdotal Evidence

Personal stories or individual experiences that add a human element to an argument.

5. • • • Example: A person describing how they quit smoking to argue for the effectiveness of support programs.

6. Quotations

Direct words from someone relevant to the topic or subject matter, often used to back up a claim.

6. • • • Example: Quoting a legal scholar in a paper on constitutional law.

7. Historical Evidence

Events or precedents from history that serve to support or discredit an argument.

7. • • Example: Referencing the Great Depression in a discussion about economic policy.

8. Logical Reasoning

Arguments based on sound logic and clear reasoning.

8. • • Example: "If A leads to B, and B leads to C, then A must lead to C."

9. Visual Evidence

Photographs, charts, graphs, and other visual materials that can support a written argument.

9. • • Example: Including a graph that shows rising carbon emissions to argue for climate action.

10. Case Studies

In-depth examinations of specific instances, events, or subjects that provide detailed insights and support for broader conclusions. Case studies are often used to illustrate how theoretical concepts apply in real-world contexts or to demonstrate the impact of certain actions or decisions.

10. • • Example: Presenting a case study on a city’s implementation of a bike-sharing program to show how it successfully reduced traffic congestion and improved public health, offering a concrete example to support arguments for sustainable urban transport solutions.