A term commonly used to describe the supporting material in persuasion.
Gives an objective foundation to your arguments, and makes them more
than a mere collection of personal opinions or prejudices.
Evidence needs to be carefully chosen to serve the needs of the claim and
to reach the target audience
Evidence plays an important role in many academic disciplines, including
science and law, adding to the discourse surrounding it.
All good arguments must be supported by a strong foundation of evidence.
The amount of evidence you need depends on the degree of controversy
of the claim you are trying to support and your credibility as an advocate.
1. Friendly Audience
they already support the advocates position
very little evidence is needed as support.
2. Neutral Audience
are waiting to see what type of support can be
provided in order to move them over to one side or the
other. The quality of evidence used is important.
3. Hostile Audience
Opposed to the advocate’s point of view. A great
deal of high-quality evidence is needed .
Precedent Evidence : is an act or event which establishes expectations for future
2 Forms: Legal & Personal
o Legal- is one of the most powerful and most difficult types of evidence to
challenge. Courts establish legal precedent.
o Personal- Occurs as a result of watching the personal actions of others in order to
understand the expectations for future behaviors.
Statistical Evidence: Consists primary of polls, surveys, and experimental results
from the laboratory.
Testimonial Evidence: is used for the purpose of assigning motives, assessing
responsibilities, and verifying actions for past, present and future events.
3 Forms: Eyewitness, Expert-witness, & Historiography
Hearsay Evidence : can be defined as an assertion or set of assertions widely
repeated from person to person, though its accuracy is unconfirmed by first hand
Common Knowledge Evidence: this type of evidence is most useful in providing
support for arguments which lack real controversy.
On order to tell us one how you know something, you need to tell them where
the information came from.
4 ways credibility of the evidence can be enhanced by:
1) Specific Reference to Source : Does the advocate tell you enough about the source
that you could easily find?
2) Qualifications of the Source: does the advocate give you
reason to believe that the source is competent
and well informed in the area in question?
3) Bias of the Source: even if expert, is the source likely to be biased on the topic?
4) Factual Support: does the source offer factual support for the position taken or
simply state personal opinions as fact?
1) Establish Conclusive Proof for your Position: using
evidence in such a way that the law will not permit
it to be contradicted, or that it is strong and
convincing enough to override objections to it.
2) Establish Circumstantial Proof for your Position:
This is where the various types of evidence are used to form a link strong
enough to prove a point. Using the different types of evidence as support gives
the argument the strength needed to establish the accuracy of the argument.
5 Tests of
1) Recency: Is the evidence too old to be current relevance to the
2) Sufficiency: Is their enough evidence to justify all of the claims
being made from it.
3) Logical Relevance: Does the claim made in the evidence
provide a premise which logically justifies the conclusion offered?
4) Internal Consistency: Does this source make claims that are
contradicted by other claims from the same source.
5) External Consistency: Are the claims made by this source
consistent with general knowledge and other evidence?
Evidence is the building block of an argument.
Evidence determines the accuracy of an argument.
Evidence is more available to us, from more sources, in a
variety of formats than ever before.
Works Cited: Marteney, Jim. Sterk Jack, Communicating Critical Thinking. Copy write 2007.