D4.4.6-8: Critiquing Arguments for Credibility

Overview

Lesson Procedure

65-70 minutes of class time across 5 phases.

1. Warm-Up10 minutes
2. Direct Instruction20 minutes
3. Guided Practice15 minutes
4. Independent Practice10-15 minutes
5. Closure10 minutes

1. Warm-Up10 minutes

   Warm-Up Prompt

   "Two classmates tell you the cafeteria will serve pizza on Friday. One says, 'The menu posted by the office says so.' The other says, 'Trust me, I'm always right.' Which argument would you believe more, and why? What would you check before you believed either one?"

   Collect answers on the board. Students usually trust the menu more because it is evidence anyone can go and check, while "trust me" is only the speaker's word. Tell students that credibility means how far an argument deserves to be believed, and that historians, scientists and economists judge arguments with the same few questions. Introduce the five questions of the Credibility Checklist (Diagram 1): Who (what does the arguer know?), Gain (what does the arguer get if we believe it?), Check (can others test the evidence?), Link (does the reasoning connect the evidence to the claim?) and Agree (do other sources corroborate, that is, back it up?).

2. Direct Instruction20 minutes

   Part 1: The giant and the sources. The question is "Which arguments about the Cardiff Giant deserved to be believed?" Stockwell's article says the hoax was planned by George Hull, a tobacconist (a tobacco seller) from Binghamton, New York. Hull had a figure of a man carved from gypsum, a soft white stone, and secretly buried it on a farm near Cardiff. In October 1869, workers digging a well "found" it. Stockwell was a doctor writing in the magazine Popular Science Monthly in June 1878, nine years later, after the hoax had been exposed. Sources 1 and 2 are two parts of his article: Source 1 tells what the first experts and visitors argued, and Source 2 tells how the case against the giant was built. Words to know: petrified means turned to stone ("petrifaction" is the turning to stone), a statue is a figure carved by a person, and the "Jesuit fathers" were Catholic priests of the Jesuit order. In Source 1, "a three-fourths interest" means a three-fourths share of ownership. In Source 2, "Solons" means lawmakers, "the modern Athens" is a nickname for Boston, "stratified" means formed in layers, and a bank "draft" is a written order to pay money.

   Source Information: who made each source, when, and from what position (from the sources and their bylines)

   Source	Maker and position	When	What it argues or reports
   1: Stockwell, part 1	G. A. Stockwell, a doctor ("M. D." in his byline), writing after the hoax was exposed	1878 (about events of 1869)	Reports the first arguments that the giant was petrified, an old statue, or of "great antiquity" (very old)
   2: Stockwell, part 2	The same writer	1878	Reports the evidence that the giant was a recent fake, and a Boston debate
   3: NOAA	NOAA's National Centers for Environmental Information, a federal science agency that keeps U.S. weather records	Published 2017, updated 2026	Argues that Phil's forecasts are often wrong for the country as a whole
   4 and 5	Invented student critiques and an invented scenario written for this page	Invented	Practice material; two critiques in Source 4 are deliberately weak

   1The following day, Sunday, four medical men of the neighborhood, of scientific pretensions, investigated the subject, swallowing the hoax without the least difficulty, pronouncing it to be a "petrified man." Later it was examined by Dr. Boynton, of Syracuse, a man possessed of some antiquarian knowledge, who decided it to be a statue "made some three hundred years ago by the Jesuit fathers," and at once offered $10,000 for it. This and more tempting offers were declined, as sightseers at half a dollar per head were apparently unlimited in number. However, Newell, in compliance with Hull's order, sold a three-fourths interest to half a dozen citizens of Syracuse for $30,000. A show-man was now placed in charge, and, in the way of advertisement, invitations were sent to Prof. Agassiz, Prof. Hull (State geologist), S. B. Woolworth (secretary of the university), etc. November 3d a large delegation of scientific men assembled from different parts of the State for deliberate and thorough inspection, who at once pronounced it a statue, the State geologist declaring it to be of great antiquity. Prof. Ward, who filled the chair of Natural Sciences in the Rochester University, said, "Although not dating back to the stone age, it is nevertheless deserving the attention of archæologists." A prominent clergyman wrote, "This is not a thing contrived of man, but is the face of one who lived like all the earth; the very image and child of God;" thus confirming the impression Hull received from his discussion with the Rev. Mr. Turk.

   1Suddenly a series of reverses overtook the giant. Prof. O. C. Marsh, of Yale College, gave it a telling blow by stating that gypsum is soluble in 400 parts of water, yet the surface of the giant was smooth and little dissolved, though surrounded by wet earth, proving that the burial must have been of very recent date. He also found other indications of fraud, which had escaped the notice of the State geologist, and other scientists; as recent tool-marks, in places where they could not be easily effaced, and adjoining water-worn surfaces. This was corroborated by Palmer, the sculptor. Soon letters were received from parties who had observed the four-horse team and load on its way to Cardiff; then one from Fort Dodge, detailing the operations in that neighborhood; and, finally, the statement of Markham, one of the stone-cutters, was obtained. Hon. Lewis Baldwin, a gentleman well versed in archaeology, remarked that the giant could neither be a finished statue nor petrifaction, as it had no hair, though complete in other respects. At last the climax was reached, which connected the person who obtained the stone from the neighborhood of Fort Dodge with the giant, by Newell drawing the money received from the Onondaga County Bank in a draft payable to Hull's order.

   [...]

   2Soon the giant came to New York, only to find itself supplanted. After a few days, it was shipped to Boston, where the excitement bade fair to break out again, from the furor created by the learned men of the modern Athens. Ralph Waldo Emerson pronounced it beyond his depth, astonishing, and undoubtedly ancient. Cyrus Cobb, the artist and sculptor, declared that any man who called the giant a humbug "simply declared himself a fool." On the 4th of February a number of Solons visited the giant as an official body. They examined it long and patiently; the exterior was tried with acids; the head bored into, and the compass carried around it in search of iron. The conclusion arrived at was very satisfactory, and undoubtedly true, as it was decided to be a "piece of stratified gypsum, probably very old." The subject invaded the Boston clubs, and one whole evening was occupied by the president of the "Thursday Evening Club" to prove that the giant was modern, because its features were Napoleonic!

   Part 2: Model the five questions. Work through Examples 1-4 aloud with the Credibility Checklist. Stress two points. First, a famous or expert person can still make a weak argument, so students check the support, not only the title. Second, Stockwell himself is a source that can be critiqued with the same five questions (students do this in the quiz). Later encyclopedias agree with his main story but not on every detail: Collier's New Encyclopedia (1921) says the gypsum was quarried at Fort Dodge, Iowa, and the New International Encyclopaedia (1905) says the stone was "sent from Ohio", so careful readers note that even the details of a well-known hoax need corroboration.

   • Who is arguing: expertise is not enough (Source 1)

     At the November 3 inspection, the state geologist declared the giant "to be of great antiquity" (Source 1). Is his argument credible just because of his job?

     Result: Not by itself. Expertise (special knowledge from study or work) makes an arguer worth hearing, but Source 1 gives no evidence or reason for his date: it reports only his verdict. Source 2, paragraph 1, says Marsh found signs of fraud "which had escaped the notice of the State geologist". Lesson: judge the argument, not only the title of the person making it.

   • What the arguer gains (Source 1)

     Dr. Boynton of Syracuse decided the giant was a statue "made some three hundred years ago by the Jesuit fathers" and "at once offered $10,000 for it" (Source 1). What does the offer tell a reader about his argument?

     Result: It shows an interest (something the arguer could gain or lose). A man trying to buy the giant had a reason to think it valuable. An interest does not make an argument false, but it means a reader should look harder for evidence. Source 1 also says Boynton had "some antiquarian knowledge" (knowledge of old objects), so he had some expertise as well.

   • Evidence others can check (Source 2)

     Professor O. C. Marsh of Yale argued that the giant was buried recently. Why is his argument more credible than the November 3 verdict?

     Result: His evidence can be tested: "gypsum is soluble in 400 parts of water" (gypsum dissolves slowly in water), yet the surface was "smooth and little dissolved" in wet earth (Source 2, paragraph 1). He also found "recent tool-marks", and "Palmer, the sculptor" agreed. A checkable fact, physical evidence and a second expert who agrees (corroboration) make a strong argument.

   • Right answer, weak reasoning (Source 2)

     In Boston, the president of the "Thursday Evening Club" argued that the giant was modern "because its features were Napoleonic" (Source 2, paragraph 2). (Napoleonic means looking like Napoleon, the French emperor.) The giant was in fact modern. Was the argument credible?

     Result: No. A face that looks like Napoleon's does not show when a stone was carved, so the reasoning does not connect the evidence to the claim. An argument can reach a true conclusion for a bad reason; credibility depends on the support, not only on the answer.

   Part 3: The same questions in another discipline. Every February 2 in Punxsutawney, Pennsylvania, a groundhog named Phil is said to "forecast" (predict) the weather. NOAA, the National Oceanic and Atmospheric Administration, checked his record against U.S. temperatures. Two terms in Source 3: the contiguous U.S. means the 48 states that touch one another, the median is the middle value when all the years are put in order, and the "20th century average" is the average for the years 1901-2000. Read Source 3 and work through Example 5.

   1Every February 2, a crowd of thousands gathers at Gobbler’s Knob in Punxsutawney, Pennsylvania, to await a special forecast from a groundhog named Phil. According to legend, if the 20-pound groundhog emerges and sees his shadow, the U.S. can expect six more weeks of winter weather. But, if Phil doesn’t see his shadow, we can expect warmer temperatures and the arrival of an early spring.

   2Even though he’s been forecasting since 1887, Phil’s track record for the entire country isn’t perfect. To determine just how accurate he is, we’ve compared U.S. national temperatures with Phil’s forecasts. On average, Phil has gotten it right 30% of the time over the past 10 years.

   3In 2025, Phil forecast “more winter” at Gobbler’s Knob when he saw his shadow and predicted six weeks of winter temperatures. In fact, the contiguous U.S. saw near-average temperatures in February and much-above-average temperatures in March of last year. Phil’s forecast was incorrect.

   4The average contiguous U.S. temperature during February 2025 was 34.8°F—1.0°F above the 20th century average. 2025 was near the median in the 131-year period of record for February.

   5Temperatures were above average across much of the Southwest, Gulf Coast and Southeast and cooler than average from the Pacific Northwest to the northern and central Plains. Arizona had its second-warmest February on record and New Mexico had its fifth warmest.

   [...]

   6March 2025 was much warmer than average (sixth warmest) in the contiguous U.S. The average temperature was 46.9°F, 5.4°F above the 20th-century average.

   [...]

   7In 1887, when he made his debut as the official groundhog forecaster for the country, Phil saw his shadow. His first prediction of six more weeks of winter was accurate for a few regions, but it came up short for several others.

   [...]

   8Predicting the arrival of springtime for an entire country—especially one with such varied regional climates like the U.S.—isn’t easy! Phil’s track record is evidence of that. However, if you’re interested in doing your own analysis for your region, check out our Climate at a Glance tool to access historical U.S. monthly temperature data. More of Phil’s past predictions are also available from the Punxsutawney Groundhog Club.

   • The same tests in earth science (Source 3)

     NOAA argues that Phil's track record "isn't perfect" and reports that "Phil has gotten it right 30% of the time over the past 10 years" (Source 3, paragraph 2). Critique this argument for credibility.

     Result: Strengths: NOAA is a federal science agency that keeps national temperature records, and it states how it checked: "we've compared U.S. national temperatures with Phil's forecasts." 30% of 10 years is 3 correct forecasts, a number readers can check. Limitation: one national average can hide regional differences, which NOAA itself describes for February 2025, when it was "cooler than average from the Pacific Northwest to the northern and central Plains" (paragraph 5).

3. Guided Practice15 minutes

   Pairs read Source 4, four invented student critiques. Tell students that two of them are deliberately weak. For each critique, pairs decide which checklist question it uses, whether it is a fair critique, and how to fix it if it is weak.

   1These four critiques were written for this page by invented students who read Sources 1-3. Two of them are deliberately weak, so that the class can find what is wrong with them. They are not models. For each one, ask which checklist question it uses and whether it treats the source fairly. A critique can reach a sensible verdict and still give a poor reason for it, so read the reason, not only the verdict.

   2Maya: "The state geologist's argument must be credible, because he was the state geologist."

   3Leo: "Professor Marsh's argument is credible because he used a fact other people could test, that gypsum dissolves in water, and he pointed to fresh tool marks that a sculptor also saw."

   4Ana: "NOAA's argument is not credible, because a government office wrote it."

   5Sam: "The Thursday Evening Club reached the right answer, but its reason, that the giant's face looked like Napoleon's, does not show when the statue was made."

   Teacher key (discussion points). Maya's critique is weak: it uses only the Who question, and Source 2 shows that the state geologist missed signs that Marsh found. A fixed version asks what evidence the geologist gave. Leo's critique is strong: it uses Check (a testable fact about gypsum), Link (a smooth surface would not survive long in wet earth) and Agree (the sculptor). Ana's critique is weak: who wrote an argument is a reason to look closely, not a reason to reject it, and Source 3 explains how NOAA checked the forecasts. A fixed version names a real limitation, such as the national average. Sam's critique is strong: it separates a true conclusion from weak reasoning.

4. Independent Practice10-15 minutes

   Each student picks two arguments from Sources 1-3, one they find credible and one they do not. For each, the student writes three to four sentences that answer at least three checklist questions and quote the source by paragraph. Students end with one sentence on the difference between a credible argument and a true conclusion.

5. Closure10 minutes

   Exit ticket: "Name one argument from today that had a famous or expert supporter but weak support. Then name the checklist question that showed the weakness."

   Teacher note on the sources: Source 1 quotes a clergyman who saw the giant as a human being and "the very image and child of God". Treat this as a historical statement of what a visitor argued, not as a question about religious belief; the lesson critiques the evidence for the giant's age, not anyone's faith. Stockwell's own credibility is assessed in Quiz Question 16, so let students judge his tone and his distance from the events themselves. Earlier parts of his article, not printed here, describe how Hull had the figure carved, shipped and "found"; one of those paragraphs quotes a remark containing a slur, which is why that paragraph is left out. NOAA's page is light in tone; the point is to practice the checklist on a clear, checkable argument.

   Quiz passage. Questions 11-14, 19 and 20 use Source 5, an invented economics scenario.

   1This scenario is invented for this page. The town, the stores, the people and all the prices are invented.

   2A new grocery store, Maple Street Market, opened in the invented town of Ridgeview, which already had one grocery store, Corner Foods. The new store's owner handed out a flyer.

   3Source 5A, the flyer: "Lowest prices in Ridgeview! We checked five items, and we beat Corner Foods on all five. Shop smart. Shop Maple Street."

   4Source 5B, the flyer's price table: bread, $2.49 at Maple Street and $2.79 at Corner Foods; a gallon of milk, $3.29 and $3.59; a dozen eggs, $2.99 and $3.19; a pound of apples, $1.49 and $1.69; a 2-pound bag of rice, $2.19 and $2.39. The flyer does not say who chose the five items or on what day the prices were checked.

   5Source 5C, a customer quoted on the flyer: "I saved a lot on my first visit!" The flyer gives only her first name.

   6Source 5D, a report by the invented Ridgeview Middle School economics club, which checked the prices of 20 common items at both stores on the same Saturday: Maple Street was cheaper on 12 items and more expensive on 8. For all 20 items together, Maple Street's total was $76.55 and Corner Foods' total was $78.40.

   Homework passage. The homework uses Source 6, an invented civics scenario.

   1This scenario is invented for this page. The town, the people and all the numbers are invented.

   2The invented town of Fernvale is deciding whether to build a splash pad in its central park. A splash pad is a summer play area where water sprays up from the ground; it has no pool of standing water.

   3Source 6A, the parks director: "Families have asked us for a splash pad for years. It will give children a safe, cool place to play on hot days." If the splash pad is approved, the parks department's budget will grow by $14,000 a year to run and clean it.

   4Source 6B, a council member: "I asked people about the splash pad, and 9 out of 10 said they want one." He does not say how many people he asked or where he asked them.

   5Source 6C, a resident at the council meeting: "Nobody goes to parks anymore. Kids just stay inside with their phones."

   6Source 6D, the parks department's gate counts at the town pool last summer: the pool averaged 410 visitors on hot days (above 85°F) and 180 on cooler days, and it was full and turned families away on 9 days. Fernvale has never had a splash pad, so there is no splash pad count.

Differentiation Strategies

Assessment Guidance

1. Question 1 of 20 · Multiple Choice

   In this lesson, what does it mean to critique an argument for credibility?

   ADecide whether you agree with its conclusion BJudge how well its support earns belief CCount how many people believe the argument DCheck whether the arguer is famous or not

2. Question 2 of 20 · Multiple Choice

   Stockwell says the four medical men who called the giant a "petrified man" were "of scientific pretensions" (Source 1, paragraph 1). What does that phrase suggest about their argument?

   AThey were the leading scientists of the state BThey had tested the stone with acids first CThey claimed more science than they showed DThey were paid by George Hull to say it

3. Question 3 of 20 · Multiple Choice

   Professor Ward said, "Although not dating back to the stone age, it is nevertheless deserving the attention of archæologists" (Source 1, paragraph 1). Archaeologists are scientists who study the human past through objects. How does Ward's statement differ from the state geologist's?

   AIt makes a smaller, more careful claim BIt proves the giant came from the stone age CIt says that the giant was a recent fake DIt gives a test anyone could repeat at home

4. Question 4 of 20 · Multiple Choice

   Lewis Baldwin, "a gentleman well versed in archaeology", said the giant "could neither be a finished statue nor petrifaction, as it had no hair" (Source 2, paragraph 1). Which checklist question shows the weakness of his argument?

   AWho: Baldwin knew nothing at all about the past BGain: Baldwin owned a share of the giant CAgree: nobody else thought it was a fake DLink: no hair does not settle what it was

5. Question 5 of 20 · Multiple Choice

   Cyrus Cobb declared that any man who called the giant a humbug (a fraud) "simply declared himself a fool" (Source 2, paragraph 2). What is the main problem with this argument?

   AIt gives too many facts about the stone BIt attacks critics instead of giving evidence CIt comes from a person with no art training at all DIt was made before the giant was found

6. Question 6 of 20 · Multiple Choice

   Ralph Waldo Emerson "pronounced it beyond his depth, astonishing, and undoubtedly ancient" (Source 2, paragraph 2). What weakens his verdict as evidence about the giant's age?

   AHe admits the question is beyond his depth BHe had bought a share of the giant earlier CHe tested the giant with acids and a compass DHe said the giant was a modern fake carving

7. Question 7 of 20 · Multiple Choice

   Source 1 says that after a show-man took charge, invitations were sent to Professor Agassiz and other scientists "in the way of advertisement" (paragraph 1). What does this detail show?

   AThe scientists had asked to buy the giant BAgassiz had already proved the giant fake CThe owners used experts' names to sell tickets DThe invitations were all sent out by Professor Marsh

8. Question 8 of 20 · Multiple Choice

   NOAA notes that Phil has "been forecasting since 1887" (Source 3, paragraph 2). Why does a long tradition not make his forecasts credible?

   AThe forecasts made before 1887 were all lost BA tradition is always wrong in the end CGroundhogs never lived in Pennsylvania DA custom's age does not test its accuracy

9. Question 9 of 20 · Multiple Choice

   NOAA writes that predicting springtime "for an entire country [...] isn't easy! Phil's track record is evidence of that" (Source 3, paragraph 8). What claim does NOAA use Phil's record to support here?

   AGroundhogs cannot see their own shadows BForecasting spring for a nation is hard CPhil is right in most regions most years DNOAA's own forecasts are always correct

10. Question 10 of 20 · Multiple Choice

    In 2025 Phil forecast more winter. NOAA reports that February 2025 "was near the median" and March was "much warmer than average", and it calls the forecast incorrect (Source 3, paragraphs 3-6). Which statement about the support for NOAA's verdict is fairest?

    AFebruary's numbers alone prove the forecast wrong BIt uses no temperature numbers at all CFebruary was near normal, so it leans on March DMarch's warmth shows the forecast was right

11. Question 11 of 20 · Multiple Choice

    What is the main weakness of the evidence in Source 5B?

    AThe prices are all given in dollars and in cents BThe store chose only five items to compare CCorner Foods wrote the price table itself DThe table compares more than two stores

12. Question 12 of 20 · Multiple Choice

    Source 5A was written by Maple Street's owner. Which checklist question does this fact raise first?

    AAgree: other stores in town printed the same flyer BCheck: nobody can visit the two stores CLink: the owner's prices prove nothing DGain: the owner profits if people believe it

13. Question 13 of 20 · Multiple Choice

    Why is Source 5C weak evidence for "Lowest prices in Ridgeview"?

    AIt is one vague report from one shopper BIt was written by the school's economics club CIt lists the prices of twenty items DIt shows that Corner Foods is cheaper

14. Question 14 of 20 · Multiple Choice

    Which source gives the most credible test of the flyer's claim?

    ASource 5A, which comes from the store owner BSource 5C, which comes from a real shopper CSource 5B, which lists five exact prices DSource 5D, which checked 20 items in a day

15. Question 15 of 20 · Short Answer

    Source 1 reports several arguments that the giant was old. Choose two of them. For each, use at least two checklist questions and quote the source to explain how credible it is.

    Show model answer

16. Question 16 of 20 · Short Answer

    Critique Stockwell himself as a source for these arguments. Name two things in Sources 1 and 2 that a reader could check and one reason to read him carefully.

    Show model answer

17. Question 17 of 20 · Short Answer

    The Boston lawmakers "examined it long and patiently": they tried acids, bored into the head and carried a compass around it, then decided it was a "piece of stratified gypsum, probably very old" (Source 2, paragraph 2). Explain why careful tests still did not make the whole conclusion credible.

    Show model answer

18. Question 18 of 20 · Short Answer

    Explain the difference between a credible argument and a true conclusion. Use one example from Source 3.

    Show model answer

19. Question 19 of 20 · Short Answer

    Rate the credibility of the flyer's claim in Source 5A: low, partly credible or high. Use Sources 5B and 5D, at least three checklist questions, and the difference between the two stores' totals in Source 5D.

    Show model answer

20. Question 20 of 20 · Short Answer

    Rewrite the flyer's claim so that it is credible, using only what Sources 5B-5D support. Then name one thing the store should check before printing it.

    Show model answer

These standards connect to D4.4.6-8: prerequisites to review first, parallel standards at the same level, and next steps that build on it.

Standard text: National Council for the Social Studies (NCSS), The College, Career, and Civic Life (C3) Framework for Social Studies State Standards: Guidance for Enhancing the Rigor of K-12 Civics, Economics, Geography, and History (Silver Spring, MD: NCSS, 2013). NCSS was not involved in the production of this lesson and does not endorse it.