Lesson_8

Lesson 8 : 

Lesson 8 How Good Is The Evidence?

Slide 2: 

What is “Evidence”? Explicit information shared by the communicator that is used to back up or to justify the dependability of a factual claim. Prescriptive Arguments: Evidence supports the reasons that are factual. Descriptive Arguments: Evidence is needed to directly support a descriptive conclusion.

The Need For Evidence : 

The Need For Evidence Factual claims are beliefs about the world that someone wishes us to accept. Can be conclusions, reasons, or assumptions. When we encounter a factual claim we should ask: Why should I believe it? Does the claim need evidence to support it? If yes, how good is the evidence?

Slide 4: 

Some factual claims can be trusted more than others. Since it is often impossible to establish the absolute truth or falsity of a claim, we prefer to ask whether a claim is dependable. Can we count on such evidence? The greater the quality and quantity of evidence, the more we can depend upon the claim.

Slide 5: 

Asking the right questions is important when trying to determine the dependability of a factual claim. Factual claims should always cause us to ask for evidence.

Slide 6: 

Asking the right questions to find the evidence: What is your proof? Where’s the evidence? Are you sure that’s true? How do you know that’s true? Why do you believe that? Can you prove it? Those with well thought out arguments will not mind answering the “right” questions.

Slide 7: 

If a person gets defensive/angry when you “ask the right questions” it might be that their “argument” is nothing more than “opinion”. Everyone may have their own opinions. Opinions are not facts. Some opinions are WRONG!

Locating Factual Claims : 

Locating Factual Claims We encounter factual claims as: Descriptive conclusions. Reasons used to support either descriptive or prescriptive conclusions. Descriptive assumptions. Examples A thru C on page 91.

Example A: “Descriptive Conclusion” : 

Example A: “Descriptive Conclusion” What is the factual claim? Frequent use of headphones may cause hearing loss. This is a descriptive conclusion supported by research evidence. Having read this descriptive conclusion we should ask, “Is that descriptive conclusion (which is a factual claim) justified by the evidence?” In other words, does the evidence support the conclusion?

Example B: “Supporting a Prescriptive Conclusion” : 

Example B: “Supporting a Prescriptive Conclusion” What is the factual claim? An increase in the number of gun related crimes over the last 10 years. This factual claim provides the reason that supports the “Prescriptive Conclusion” that “This country needs tougher gun regulations”. The question we must ask is, “Is that reason (a factual claim) justified by the evidence?”

Example C: “Descriptive Assumption” : 

Example C: “Descriptive Assumption” What is the conclusion: “Our country needs to decrease its dependency on fossil fuels.” The reasons: Hybrids lower gas and oil consumption. Government needs to pursue alternative energy sources at all costs because dependence upon fossil fuels (such as oil) leads our country to unfavorable international actions. The descriptive assumption, which is the factual claim, will link the reasons and the conclusion.

What is the descriptive assumption? : 

What is the descriptive assumption? “The monetary (financial) costs of switching to hybrid cars and alternative energy sources are far less than the political benefits to decreasing dependency on fossil fuels.” That descriptive assumption is a factual claim. The question we must ask is: Does the evidence support the descriptive assumption? When the factual claim is an assumption, the speaker/author will rarely present direct supporting evidence.

Sources of Evidence : 

Sources of Evidence How and when do we know that evidence is dependable? When the factual claim appears to be undisputed common knowledge. When the factual claim is the conclusion from a well-reasoned argument. When the claim is adequately supported by solid evidence in the same communication or by other evidence we know.

Review: What is evidence? : 

Review: What is evidence? Your book defines evidence as follows: “Evidence is explicit information shared by the communicator that is used to back up or to justify the dependability of a factual claim.” “In prescriptive arguments, evidence will be needed to support reasons that are factual claims.” “In descriptive arguments, evidence will be needed to directly support a descriptive conclusion.” You Already Have This Information!

Slide 15: 

How do we determine the quality of evidence? I.e.…how good is the evidence? First ask, “What kind of evidence is it?” Once we have identified the type of evidence we are better able to determine if the evidence is dependable.

Intuition as Evidence : 

Intuition as Evidence Intuition: A process in which we believe we have direct insights about something without being able to consciously express our reasoning. Common sense, gut feeling, or hunch. Valuable when backed up by extensive relevant experiences and readings. As critical thinkers we should ask, “Is this claim based on any other evidence?” Problem with Intuition: Private and not verifiable. Be wary of intuition as evidence.

Personal Experience and Anecdotes as Evidence : 

Personal Experience and Anecdotes as Evidence Personal experiences are often very vivid in our memories and we often rely on them as evidence to support any particular belief we may have. This can be very dangerous because our experiences are not broad enough to provide any real evidence for a factual claim. Relying upon personal experiences as evidence often leads to the “hasty generalization fallacy”.

Personal Experience and Anecdotes as Evidence : 

Personal Experience and Anecdotes as Evidence A single experience, or a series of experiences, may tell us that such outcomes are possible but such experiences do not tell us that those outcomes are typical or probable. We should always use caution when basing a conclusion upon personal evidence and/or anecdotes. Use caution when you read/hear someone say, “I know someone who…” or “In my experience, I’ve found…”

Testimonials as Evidence : 

Testimonials as Evidence A testimonial is when someone tries to persuade you of something by using a special kind of appeal to personal experience; they quote particular persons, cite extraordinary events, etc. This type of evidence is usually not dependable as evidence. In most cases we should pay little attention to personal testimonials until we find out more about the expertise, interests, values, and biases that may lay behind them.

Problems with Testimonials: : 

Problems with Testimonials: Selectivity: People carefully select the testimony they use based on what they believe or what they want to be true. Personal interest: Many testimonials come from people who have something to gain from their testimony. We should always ask, “Does the person providing the testimony have a relationship with what he/she is advocating? If so, how will that relationship affect his/her testimony?”

Problems with Testimonials: : 

Problems with Testimonials: Omitted information: Testimonials rarely provide sufficient information about the basis for the judgment. The Human Factor: Testimonials are often provided by people who have strong feelings about something or someone. However we need to ask ourselves if there is any other reason we should accept their testimony.

Appeals to Authority as Evidence : 

Appeals to Authority as Evidence Authorities are sources that are suppose to know more than most of us about a given topic, they are experts. When authors or speakers appeal to authorities or experts, they appeal to people that they believe are in a position to have access to certain facts and have qualifications for drawing conclusions from those facts. Appeals to authority can potentially provide strong evidence for conclusion.

Appeals to Authority as Evidence : 

Appeals to Authority as Evidence Look at the list of authorities on page 97. Some appeals to authority should be taken much more seriously than others. When a person is a recognized authority in a particular area in question and when they have carefully examined and explained their position, we should pay attention to them. We need to be very careful about accepting appeals to authority from questionable sources.

Appeals to Authority as Evidence : 

Appeals to Authority as Evidence Keep in mind that authorities: Can be wrong. Can and do disagree. Example: Bottom of page 97.

Slide 25: 

Critical Questions: Why should we believe this authority? How much expertise or training does the authority have about the subject about which he/she is communicating? Was/is the authority in a position to have especially good access to important information about the topic? (Ex: Eyewitness or second-hand information).

Slide 26: 

Critical Questions: Is there good reason to believe that the authority or expert is relatively free of distorting influences? Has the authority developed a reputation for frequently making dependable claims? Have we been able to rely on this authority in the past? Assessing websites video.

Group Activity : 

Group Activity Page 101-102 – Passage 3

Class Assignment : 

Class Assignment Research the issue, "Should seatbelts be required on all school buses?" Write a short paragraph in which you: Identify the different types of evidence you found. Specifically look for and identify the following types of evidence: Intuition, Personal Experience, Testimonials, and Appeals to Authority. Try to find examples of at least one or two of those types of evidence. Determine the quality of the evidence. Make sure you base your judgment of the evidence on your reading of chapter 8.