Write a discipline-specific argument from sources with a thesis, counterclaim and formal conclusion

Learning goal: Write an argument focused on discipline-specific content in history or science: establish a clear thesis statement, introduce a claim and distinguish it from alternate or opposing claims, organize reasons and evidence logically, support the claim with logical reasoning and relevant, accurate data from credible sources, use words and phrases that create cohesion, keep a formal style, and provide a concluding statement that follows from and supports the argument.

An argument in a history or science class is different from an argument in an English class about a novel. The claim is about the world: what caused an event, which explanation fits the data, or which design meets a requirement. The evidence has to suit that question: a document, a table of measurements, a map or a record. A novel or a character's speech can be evidence about how people of a period thought or wrote, but it cannot by itself establish that a real event happened or what caused it. A good discipline-specific argument therefore begins with a question the discipline actually asks, and it answers that question with the discipline's kind of evidence.

The historical question and the sources. Everything in this lesson's model is invented for instruction. The town of Calder Bend, its people and its records do not exist, so nothing here should be quoted as a fact about any real place. The general pattern is real: many towns that grew along canals in the first half of the 1800s lost trade when railroads were built, but any claim about an actual town must be checked against actual records. The question is: Why did Calder Bend lose population between 1850 and 1870? The source packet has four fictional items.

Source A — county population table (fictional). Calder Bend: 1,240 people in 1850; 1,190 in 1860; 860 in 1870. Reedsville, nine miles north: 410 in 1850; 620 in 1860; 1,480 in 1870.

Source B — letter from a Calder Bend storekeeper to his brother, dated 1868 (fictional). "Since the cars began stopping at Reedsville the grain wagons go north instead of down to our landing. Six shops on Water Street have closed. The canal boats still come, but slowly, and a man can wait a week for a load."

Source C — notice in a county newspaper, 1861 (fictional). "The railroad company has surveyed its line through Reedsville, where the ground is level, and will not bring the track to Calder Bend on account of the river bluffs."

Source D — county history written in 1880 (fictional). "Many young men from every township in the county, Calder Bend and Reedsville alike, enlisted in 1861 and 1862: the muster roll lists 44 men from Calder Bend and 40 from Reedsville, and 9 and 8 of them did not return. Others found work in the cities after the war."

Establish a clear thesis statement. A thesis in an argument states the position the whole essay will defend, in words that could be disagreed with. In a short argument like this one it is usually a single sentence; a longer essay sometimes needs two, such as a concession followed by the claim. "Calder Bend lost people" only restates the question. "Calder Bend lost population mainly because the railroad bypassed the town and carried its trade to Reedsville" is a thesis: it names a cause, ranks it as the main one, and can be tested against the sources. Notice the word mainly. A thesis that says only would be contradicted by Source D; a thesis that says partly is defensible but promises less: it fits an argument whose evidence can show that a cause mattered without ranking it. Choose the strength the evidence can carry, and no more.

Introduce the claim and distinguish it from opposing claims. A reader who knows the sources will immediately think of the alternate claim: the Civil War took the young men away. If the essay ignores that claim, the reader supplies it and trusts the writer less. So the introduction acknowledges the opposing claim and states how the essay will distinguish its own: "Some of the loss followed the war, as the county history notes, but the timing and the size of the decline point to the railroad." Acknowledging a counterclaim is not surrender. It shows the writer understands the topic, and it sets up the reasons.

Organize reasons and evidence logically. A logical order for this argument moves from the strongest, most specific evidence to the counterclaim and its limits. Reason one is about timing: the population fell by only 50 people between 1850 and 1860 and by 330 between 1860 and 1870, the decade in which the railroad decision came, in 1861. Notice what the table cannot do: it counts once every ten years, so it cannot show in which years of that decade the people left. Reason two is about mechanism: Sources B and C explain how the railroad took the trade, so the numbers have a cause behind them and are not a coincidence. Reason three addresses the counterclaim: the war explains some loss, but Reedsville sent about as many men to the same war, lost about as many (Source D), and still more than doubled. A war that struck both towns about equally cannot by itself explain why one town shrank while its neighbor grew. The comparison limits the counterclaim; it does not measure how many of the people who left Calder Bend left because of the war, for example to find work in the cities. A different order, such as counterclaim first, can work if the writer explains why, but reasons should never be listed in the order the writer happened to think of them.

Support with logical reasoning and relevant, accurate data. Evidence is only as strong as the reasoning that connects it to the claim. "Population fell 330 people from 1860 to 1870" is data. "That is about 28 percent of the 1860 population, compared with a 4 percent loss in the previous decade, so the loss accelerated in the decade of the railroad decision" is reasoning; it shows the reader why the number matters. Check every calculation: 330 ÷ 1,190 = 0.277, so "about 28 percent" is accurate; 50 ÷ 1,240 = 0.040, so "about 4 percent" is accurate. Say which source each number comes from, and say what kind of source it is. A newspaper notice from 1861 is credible evidence of what the railroad announced; it is not evidence of what happened afterward, which is why the 1868 letter is needed too. In a science argument the same rule applies: a claim that a longer pendulum swings more slowly must cite the measured times and explain the pattern, not just assert it.

Create cohesion with words, phrases and clauses. Cohesion words tell the reader how each sentence relates to the last one. Because and since introduce reasons. In contrast and however introduce a counterclaim or a limit. For example and according to Source B introduce evidence. Although the war took some men, the town's neighbor grew is a complex sentence: its dependent clause, Although the war took some men, carries the counterclaim, and its independent clause, the town's neighbor grew, carries the answer, so one sentence holds both. These words do not make reasoning valid on their own; "the war happened, therefore the railroad caused the decline" is still a non-sequitur. Use them to clarify relationships that the evidence actually supports.

Establish and maintain a formal style. Formal style in a history or science argument means precise nouns, no slang, no first-person feelings in place of evidence, and no insults toward the opposing claim. "The war argument is dumb" becomes "The war cannot be the whole explanation, because Reedsville faced the same war and grew." Formal does not mean stiff; it means every sentence could be read aloud to a historian without embarrassment.

Provide a concluding section that follows from the argument. The conclusion restates the thesis in the light of what was shown, states what the evidence cannot settle, and stops. It does not add a new reason and it does not exaggerate: after an argument built on four fictional sources, "this proves beyond any doubt" would be false even if the sources were real.

Original model argument — Why Calder Bend Emptied (fictional sources). Between 1850 and 1870 Calder Bend shrank from 1,240 people to 860 while Reedsville, nine miles north, grew from 410 to 1,480. Some of that loss followed the Civil War, as the 1880 county history notes. However, the timing and the size of the decline point to a different main cause: Calder Bend lost population mainly because the railroad bypassed the town and carried its trade to Reedsville.

First, the timing fits the railroad and not the war alone. According to the county table (Source A), the town lost 50 people between 1850 and 1860, about 4 percent. In the next decade it lost 330, about 28 percent. The railroad company announced in 1861 that its line would pass through Reedsville "on account of the river bluffs" (Source C). The sharp loss falls in the decade in which the track was laid elsewhere. The table counts only every ten years, so it cannot show in which years of that decade the people left; the timing is consistent with the railroad explanation rather than proof of it.

Second, the sources explain how the railroad removed the town's reason to exist. A canal landing lived on the wagons that brought grain to the boats. The storekeeper's 1868 letter (Source B) reports that "the grain wagons go north instead of down to our landing" and that six shops on Water Street had closed. Because the wagons went to the railroad, the shops that served the wagon trade lost their customers; the letter does not say where the shopkeepers went, but a street that has lost six shops gives families fewer reasons to stay. The numbers in Source A are consistent with the process described in Source B.

Some readers will point to Source D: young men enlisted in 1861 and 1862, and some never returned. That is true and it accounts for part of the loss. Yet the same county history counts about as many volunteers and about as many dead from Reedsville (40 and 8) as from Calder Bend (44 and 9), and Reedsville more than doubled between 1860 and 1870. A war that struck both towns about equally cannot, on its own, explain why one shrank while the other grew; something that differed between the two towns must account for the difference, and the sources name one such difference, the railroad. This comparison does not rule the war out. The 9 men who did not return are a small part of the 330 residents Calder Bend lost between 1860 and 1870, but the sources cannot say how many of the others left because of the war, for example to find work in the cities. The comparison shows that a war-only explanation fails and makes the railroad the stronger explanation; it does not measure the railroad's share.

In conclusion, the population table, the newspaper notice and the storekeeper's letter are consistent with a single story: when the track went to Reedsville, the trade and then the people followed it. The war took some residents in the same decade, and because the table counts only every ten years, the sources cannot separate the two causes year by year; the argument rests on the mechanism the letter describes and on the comparison with Reedsville. The sources do not say how many families moved to Reedsville itself, so that question remains open.

Worked thesis repair: A draft begins, "In this essay I will talk about why Calder Bend got smaller." This is an announcement, not a thesis: it takes no position and could not be disagreed with. Revised: "Calder Bend lost population mainly because the railroad bypassed the town." The revision names a cause and ranks it, so each paragraph now has a job: to show that the railroad, more than the war, explains the loss, and to say how far the evidence can rank the two.

Worked evidence-and-reasoning check: A student writes, "Source A shows the railroad caused the decline." Source A is a population table; it shows when the decline happened, not what caused it. The repair separates data from reasoning: "Source A shows the loss jumped from 50 people to 330 people between the two decades. Source C dates the railroad's decision to 1861, at the start of the second decade. Together they suggest the railroad, because the larger loss falls in the decade of the decision; the table cannot show the exact years, so suggest is the right verb." Now each source is used for what it can actually show, and the calculation (330 − 50 = 280 more people lost in the second decade) can be checked.

Worked counterclaim paragraph: A draft says only, "Some people think it was the war, but it wasn't." The counterclaim is named but neither explained nor answered. Revised: "Source D reports that many young men enlisted and some did not return, so the war certainly removed some residents. However, Reedsville sent about as many men, lost about as many, and grew from 620 to 1,480 between 1860 and 1870. A war that struck both towns about equally cannot by itself explain why only one of them shrank, so the war is at most part of the story, and the sources cannot say how large a part." The revision states the opposing claim fairly, grants what is true in it, and uses a comparison to limit the counterclaim without pretending to measure it.

Worked science version of the same skills: A science argument follows the same structure with different evidence. Thesis: "The length of a pendulum, not the mass of the bob, determines how long a swing takes." Evidence: in a class trial (model data), ten swings took 10.0 s at 25 cm, 14.2 s at 50 cm and 20.1 s at 100 cm, while doubling the bob's mass at 50 cm changed the time by only 0.1 s. Reasoning: the time changed with length every trial and did not change measurably with mass, so length is the variable that matters. Counterclaim: "the heavier bob should fall faster." Answer: the measurements show no such effect, and gravity accelerates all masses equally when air resistance is small. Conclusion: for small swings, length controls the period.

Source annotation task: Using the four fictional Calder Bend sources, make a two-column chart. In the left column copy the exact words or numbers you would use as evidence; in the right column write one sentence of reasoning that connects that evidence to either the railroad claim or the war counterclaim. Mark each source with what it can and cannot show (a table shows amounts, not causes; a letter shows one person's view in one year). Then write your thesis in one sentence and number your reasons in the order you will present them, with a one-line justification for the order.

Independent performance: Write a 400- to 500-word argument answering the Calder Bend question, or a question from your current history or science unit that your teacher approves, using at least three sources. Success criteria: (1) a one-sentence thesis that takes a position and can be disagreed with; (2) an introduction that names the opposing claim and distinguishes yours from it; (3) at least two reasons in a stated logical order, each supported by relevant, accurate data or quotations with the source identified; (4) at least one calculation or comparison that a reader can check; (5) cohesion words that correctly signal reason, evidence, contrast and conclusion; (6) formal style throughout, with no insults to the opposing view; (7) a concluding section that follows from the reasons and names one thing the evidence leaves open. Exchange drafts with a partner who reads only your thesis and your conclusion and reports whether they match; revise until they do.