Conflicting Viewpoints Passage — ACT Science

Introduction

The Conflicting Viewpoints passage is unlike any other on ACT Science. No graphs, no tables — just two scientists arguing. Students who try to figure out who is 'right' waste time. Students who map each viewpoint score perfectly.

Conflicting Viewpoints has 7 questions — the most of any passage type. Students who skip it sacrifice 7 of 40 points. Systematic approach makes it a reliable scoring opportunity.

By the end of this lesson you will be able to:

Map the key claims of each scientist before answering any questions
Correctly attribute a specific claim, prediction, or assumption to the right scientist
Evaluate whether new evidence supports, weakens, or is irrelevant to each viewpoint

You will analyze two scientists debating mass extinction causes and practice all question types: attribution, agreement/disagreement, and new-evidence evaluation.

The Concept

The Core Rule

You are not asked to decide who is correct. You are asked to understand what each scientist claims and evaluate evidence against those specific claims. Stay in each scientist's perspective as defined in the passage.

How the ACT tests this

Attribution: 'According to Scientist 2, what causes X?'
Agreement/disagreement: 'On which point do Scientist 1 and 2 agree?'
New evidence: 'If researchers found Y, how would this affect each viewpoint?'

Pre-Reading Strategy: Map Before You Answer

Spend 90 seconds creating a two-column map. Write each scientist's main claim, evidence, and prediction. This pays off immediately — most questions can be answered from your map without re-reading.

Scientist 1: main claim, 2–3 supporting points, one prediction
Scientist 2: same structure
Agreement row: shared premise (usually the phenomenon exists)
Disagreement row: core point of conflict

Question Types

Four categories: (1) content — what does Scientist X claim? (2) comparison — agree/disagree? (3) new evidence — how does finding Y affect viewpoints? (4) assumption — what must Scientist X assume?

Content: go to the relevant scientist's column in your map
Comparison: check both columns for the specific claim
New evidence: evaluate finding against each scientist's mechanism separately
Assumption: what must be true that is not explicitly stated?

Evaluating New Evidence

Identify which scientist's mechanism the finding relates to. Determine if consistent or inconsistent. Select the answer that correctly labels each viewpoint's reaction.

Consistent with Scientist 1's prediction → supports Scientist 1
Contradicts Scientist 2's required assumption → weakens Scientist 2
Neither depends on the finding → irrelevant to both
Can simultaneously support one and weaken the other

Your strategy

Step 1 — Read introduction: what is the topic of disagreement? Create two-column map header.
Step 2 — Read Scientist 1, write: main claim, 2–3 supporting points, one prediction.
Step 3 — Read Scientist 2, do the same. Note explicit contradictions.
Step 4 — For each question: identify type, go to relevant column(s), answer from your map.

Worked Examples

Easy Example 1 Iridium Is Mentioned In Both Scientists' Arguments But In Opposite Ways. Always Attribute Evidence To The Scientist Who Cited It.

Scientist 1 (Asteroid Impact): a large asteroid caused mass extinction 66 million years ago via dust blocking sunlight, cooling the planet. Evidence: iridium deposit worldwide. Extinction appears geologically sudden. Scientist 2 (Volcanic Activity): massive Deccan Traps eruptions released CO₂ over 300,000 years, gradual climate change stressed ecosystems. Evidence: fossil diversity declines gradually beginning 300,000 years before the iridium layer.

No figure. Passage text only.

According to Scientist 2, what is the primary evidence that the extinction was gradual rather than sudden?

A. Presence of iridium in 66-million-year-old rock layers
B. Chemical composition of Deccan Traps volcanic gases
C. Fossil records showing gradual diversity decline beginning 300,000 years before the iridium layer (Correct answer)
D. Cooling of global temperatures after dust deposition

Step 1

Step 1 — Question type: content (Scientist 2's evidence). Go to Scientist 2 column.

Step 2

Step 2 — Scientist 2 explicitly cites fossil records showing gradual decline over 300,000 years.

Step 3

Step 3 — Match to options: Option C states exactly this.

Step 4

Step 4 — Verify: iridium (A) and dust cooling (D) are Scientist 1's evidence. Answer: C.

Correct answer: C

Why C is correct

Scientist 2 explicitly states this. Correct.

Why other options are wrong

A: Iridium is Scientist 1's evidence for impact. Incorrect.

B: Not explicitly cited as evidence for gradual extinction in the passage. Incorrect.

D: Dust cooling is Scientist 1's mechanism. Incorrect.

⚠ Trap: Iridium is mentioned in both scientists' arguments but in opposite ways. Always attribute evidence to the scientist who cited it.

Medium Example 2 ACT Agreement Questions Often Involve The Implicit Shared Premise — The Phenomenon Both Are Trying To Explain. Look For What Both Scientists Accept Without Arguing About.

Same asteroid vs. volcanic passage.

Same passage text.

On which point do Scientist 1 and Scientist 2 AGREE?

A. Extinction was caused by a single catastrophic event
B. A mass extinction occurred approximately 66 million years ago (Correct answer)
C. Deccan Traps eruptions were the primary driver of climate change
D. The iridium layer is evidence of an asteroid impact

Step 1

Step 1 — Question type: comparison. Check both columns for shared claims.

Step 2

Step 2 — Both scientists reference the extinction event ~66 million years ago as what they are explaining.

Step 3

Step 3 — Disagreements: cause (impact vs volcano), pace (sudden vs gradual), iridium interpretation.

Step 4

Step 4 — Agreement: the extinction event happened ~66 million years ago. Answer: B.

Correct answer: B

Why B is correct

Both scientists accept the extinction as the shared premise. Correct.

Why other options are wrong

A: Scientist 1 agrees; Scientist 2 explicitly disagrees. No agreement. Incorrect.

C: Scientist 2 argues this; Scientist 1 does not. No agreement. Incorrect.

D: Scientist 1 argues this; Scientist 2 uses iridium as a timeline marker only. No clear agreement. Incorrect.

⚠ Trap: ACT agreement questions often involve the implicit shared premise — the phenomenon both are trying to explain. Look for what both scientists accept without arguing about.

Hard Example 3 Students May Reflexively Weaken Both Scientists Out Of General Skepticism. ACT New-evidence Questions Have Specific Correct Answers Based On Logical Consistency With Each Viewpoint's Stated Claims.

Same passage. New finding: species diversity dropped sharply within a single geological layer (~10,000 years), not gradually over 300,000 years. Iridium deposit is present worldwide at this boundary.

No figure. New evidence in question stem.

How would this new finding most likely affect the two scientists' viewpoints?

A. Support Scientist 1 and weaken Scientist 2 (Correct answer)
B. Support Scientist 2 and weaken Scientist 1
C. Support both equally
D. Weaken both

Step 1

Step 1 — Finding: (a) sharp drop in 10,000 years, (b) worldwide iridium at boundary.

Step 2

Step 2 — Scientist 1 (sudden catastrophic impact): sharp extinction = sudden = supports. Worldwide iridium = asteroid origin = supports.

Step 3

Step 3 — Scientist 2 (gradual over 300,000 years): explicitly argued gradual decline. Sharp 10,000-year drop contradicts this. Weakened.

Step 4

Step 4 — Answer: supports Scientist 1, weakens Scientist 2. Option A.

Correct answer: A

Why A is correct

Sudden extinction contradicts Scientist 2's gradual mechanism and supports Scientist 1's catastrophic event. Correct.

Why other options are wrong

B: Opposite of what the finding shows. Incorrect.

C: Finding contradicts Scientist 2's core premise — cannot equally support both. Incorrect.

D: Scientist 1 is directly supported — not weakened. Incorrect.

⚠ Trap: Students may reflexively weaken both scientists out of general skepticism. ACT new-evidence questions have specific correct answers based on logical consistency with each viewpoint's stated claims.

Strategy Tips

Create a two-column map before reading any questions — 90 seconds, pays off on 5 of 7 questions
For attribution: use the passage, not your science knowledge
For agreement: look for the shared premise — both accept the phenomenon exists
For new evidence: evaluate each scientist's mechanism separately and objectively
Never decide who is 'actually right' — ACT rewards accurate reading, not scientific judgment

Common pitfalls

Mixing up which scientist claimed which evidence

Answering new-evidence questions based on real-world science knowledge

Skipping the pre-reading map to save time — this always backfires

Budget 8–9 minutes total: 90 seconds to map, then 60–75 seconds per question. Do not rush the map.

Summary

Map each scientist's main claim, evidence, and prediction before any questions
Attribute claims accurately by tracking which column they belong to
For new evidence: evaluate against each scientist's stated mechanism separately

Find two opinion articles on the same scientific topic. Create a two-column map of each author's claim, evidence, and prediction. Write one finding that supports Author 1 and weakens Author 2, and one that does the reverse.

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