By Harold Garcia

Chapter 11: Evidence

What is Evidence?• The available body of facts or

information indicating whether a belief or proposition is true or valid.

• Evidence is the Foundation of an argument

• Evidence establishes the amount of accuracy on your argument

This is determined based on the demands of the target audience

Friendly Audience: Already Supports the advocate position on a claim, so very little evidence is needed

Neutral Audience: One that has made no commitment to adhere to the advocated point of view. The evidence needed can go either way

Hostile Audience: This group is opposed to the advocate’s point of view; in this case a great deal of evidence is needed

How Much Evidence Is Needed?

•Precedent Evidence: An act or event which establishes expectation for future conduct

•Statistical Evidence: Composed of polls, surveys, and experimental results

•Hearsay Evidence: Referred to as assertions widely repeated from person to person. It’s accuracy is not confirmed, also know as rumor or gossip evidence

•Testimonial Evidence: This is used to assign motives, assessing responsibilities, and verifying actions for past, present, and future events. This testimony is an opinion of reality stated by another person. There are three forms (Eyewitness, Expert-Witness, and historiography)

•Common Knowledge Evidence: Evidence which usually does not require further evidence due to it’s nature. People just accept it as true.

Credibility of Evidence•In order to tell us how you know something, you need to tell us where the information came from. The credibility of the evidence used can be supported by:

•Specific Reference to Source: Does the advocate give you enough details about the source that you can find the information yourself?

•Qualifications of the Source: Does the Advocate give enough reasons to believe that the source has accurate and valid information, with enough information about the claim in question.

•Bias of the Source: Even if the source is accurate, valid or an expert on the topic. Is the source likely to be biased due to knowledge of job, political party or an organization he/she works for?

•Factual Support: Can the source provide enough support for the position taken, or is their position simply a personal opinion?

Establish conclusive proof in such a way that the law will not allow it to be contradicted

Form circumstantial proof to form a link strong enough to prove your point.

Create an evidence chain. Put together as much evidence possible to establish the accuracy of the claim. Use different types of evidence.

Using Evidence

To make sure strong evidence has been acquired, it must be put to the test.

Evidence must be accurate

Evidence must be trusted and reliable

There are multiple steps that can be used to test evidence.

Test of Evidence

Regency: Evidence too old to be relevant to current issues

Sufficiency: Is the evidence enough? Is it sufficient for all the claims being made?

Logical Relevance: Does the claim justifies the conclusion offered? Can the conclusion be drawn based on the evidence provided?

Internal Consistency: Does the source make claims contradicted by other claims?

External Consistency: Are the claims consistent with the general knowledge and other evidence provided? And if discrepancies occur, can the writer account for them?

Test of Evidence

Evidence is the foundation of an argumentThe amount of evidence needed depends on

the target audienceThere are 5 types of audiencesEvidence must be credible and reliableUse different types of evidence to create a

strong chain Put evidence to the test to make sure it’s

accurate and reliable

What Did We Learn?