Logical Reasoning Foundations: Building and Revising Better Arguments

Build Better Arguments by Revising, Not Just Defending

In real life, most arguments start as rough drafts: a quick complaint, a rushed recommendation, a persuasive pitch. Revising an argument means improving the reasoning so that (1) the conclusion says exactly what you mean, (2) the premises actually support that conclusion, and (3) the support is relevant and strong enough for the level of confidence you’re asking for.

This chapter focuses on constructive repair moves: making the conclusion precise, adding premises that directly address the gap, removing irrelevant reasons, strengthening evidence, qualifying the conclusion, and stating assumptions openly.

Step 1: Make the Conclusion Precise (So You Know What You’re Trying to Prove)

Vague conclusions are hard to support because you can’t tell what would count as enough evidence. Precision usually improves an argument immediately.

Common ways conclusions are imprecise

• Unclear action: “We should do something about parking.” (What action?)
• Unclear scope: “This policy is bad.” (Bad for whom? in what way?)
• Unclear timeframe: “Prices will go down.” (When?)
• Unclear standard: “The service is unacceptable.” (Compared to what expectation?)

Practical rewrite checklist

• Turn “should” into a specific action: who should do what by when.
• Replace broad evaluative words (“bad,” “great,” “unfair”) with a measurable claim (cost, time, error rate, safety, satisfaction).
• Add scope words: “in this neighborhood,” “for new users,” “for orders under $50.”
• Choose a confidence level word that matches your support: “must,” “probably,” “might,” “is worth testing.”

Step 2: Add Premises That Directly Address the Gap

After you’ve made the conclusion precise, ask: “If someone accepted my premises, would they have a good reason to accept this exact conclusion?” If not, you need premises that connect the evidence to the claim you want.

Gap-filling prompts (use one at a time)

• Mechanism: “How does this cause that?”
• Rule/standard: “What principle makes this count as acceptable/unacceptable?”
• Comparison: “Compared to what alternative?”
• Representativeness: “Is this example typical or a one-off?”
• Feasibility: “Can the proposed action realistically be done with available resources?”
• Trade-offs: “What costs or downsides matter for this decision?”

Mini-template: evidence to decision

Evidence (facts/data) + Bridge premise (rule/standard/mechanism) + Context (constraints/trade-offs) => Conclusion (specific action/claim)

Step 3: Remove Irrelevant Reasons (Support That Doesn’t Actually Support)

Many everyday arguments contain reasons that are emotionally compelling but logically idle. Removing them makes the argument clearer and often more persuasive because the remaining support is easier to evaluate.

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Quick relevance tests

• “Even if true, would it change the likelihood of the conclusion?” If no, it’s irrelevant.
• “Does it support a different conclusion than the one stated?” If yes, either change the conclusion or remove the reason.
• “Is it just a restatement?” “We should do X because X is good.” That’s not support.

Common irrelevant add-ons to cut

• Attacks on a person’s character when the issue is about evidence or policy.
• Popularity claims when the conclusion is about effectiveness or truth.
• Unrelated anecdotes that don’t represent the general case.

Strengthening Moves: Three Ways to Make Support More Justified

1) Improve the evidence (quality over quantity)

Instead of adding more reasons, upgrade the ones you have.

• Make evidence specific: “Late” becomes “arrived 22 minutes after the scheduled time.”
• Use appropriate comparisons: “Higher than last month” becomes “12% higher than the 6-month average.”
• Use multiple independent indicators: not just one metric or one story.
• Check alternative explanations: note what else could explain the observation and whether you ruled it out.

2) Qualify the conclusion (match strength to support)

If your evidence supports a cautious claim, don’t overstate it. Qualification is not weakness; it is accuracy.

• Overstrong: “This will fix the problem.”
• Qualified: “This is likely to reduce the problem in the next quarter.”
• Testable: “We should pilot this for 30 days and measure X and Y.”

3) State assumptions openly (so others can evaluate them)

When assumptions stay hidden, disagreements become personal or confusing. When assumptions are explicit, people can discuss the real hinge points.

• Examples of useful explicit assumptions: “Assuming the survey sample reflects our customer base,” “Assuming the budget cap is firm,” “Assuming delivery delays are mainly due to staffing rather than weather.”

Before-and-After Rewrites (Everyday Arguments)

Example 1: A request at work

Before (rough draft): “Can we get a second monitor for me? It would really help, and everyone else has better setups.”

Problems to revise: vague benefit (“help”), irrelevant comparison (“everyone else”), missing standard (why is this justified spending?).

After (revised): “I’m requesting a second monitor this month so I can review documents while updating the database without constant window switching. Over the last two weeks, I tracked an average of 25 minutes per day lost to switching and re-checking fields. A second monitor costs about $180 and would likely pay for itself within a month in recovered time, assuming my workload stays similar.”

Example 2: A complaint to a service provider

Before (rough draft): “Your service is unacceptable. I’ve been a loyal customer for years, and this is ridiculous.”

Problems to revise: unclear standard, no specifics, loyalty doesn’t show what went wrong.

After (revised): “On January 18, my order (#4821) arrived 3 days after the promised delivery date and the item was damaged (photos attached). Because the delivery guarantee on your site states 2-day shipping for my plan, I’m requesting either a replacement shipped with expedited delivery or a refund of the shipping fee. If you need confirmation, I can provide the tracking history.”

Example 3: A recommendation to a friend

Before (rough draft): “Don’t buy that laptop. The brand is terrible and people online hate it.”

Problems to revise: vague conclusion (which model?), popularity as weak support, missing criteria (what matters to the friend?).

After (revised): “Given you need a laptop for video editing and travel, I recommend choosing a model with at least 16GB RAM, a dedicated GPU, and a battery that reliably lasts 8+ hours. The model you’re considering has 8GB RAM and integrated graphics, which will likely slow rendering and multitasking. If you want to stay near that price, two alternatives that meet your requirements are Model A and Model B; both have 16GB RAM and dedicated GPUs in the same weight range.”

Example 4: A policy suggestion in a group chat

Before (rough draft): “We should ban cars from the street. It’s dangerous and the city never listens anyway.”

Problems to revise: conclusion too broad, irrelevant frustration, missing feasibility and trade-offs.

After (revised): “I propose we request a 6-month pilot that restricts through-traffic on Oak Street during school arrival and dismissal (7:30–8:30 and 2:30–3:30). The goal is to reduce near-misses and speeding at those times. This is feasible because there are parallel routes one block over, and residents would still have access via permits. If the city agrees, we can evaluate the pilot using speed measurements and incident reports before deciding on a permanent change.”

A Practical Revision Workflow You Can Reuse

Use this sequence when you want to improve an argument quickly without getting lost.

1. Write the conclusion as one sentence with a specific action/claim, scope, and timeframe.
2. List your current premises (only the ones that are supposed to support the conclusion).
3. Circle the “bridge” point: what must be true for those premises to make the conclusion likely?
4. Add one bridge premise that directly connects the evidence to the conclusion (standard, mechanism, comparison, feasibility, or trade-off).
5. Delete one irrelevant or redundant premise (keep the strongest support).
6. Upgrade one piece of evidence (make it more specific, more representative, or better measured).
7. Adjust the conclusion strength (qualify, narrow scope, or propose a test/pilot).
8. State key assumptions explicitly (the ones someone could reasonably dispute).

Capstone Activity: Revise a Real-World Argument (News Snippet or Ad)

Choose a short argument

Pick one of these sources (keep it to 2–6 sentences):

• a news snippet summarizing a policy proposal
• a product ad claim (including a social media post)
• a short editorial paragraph

Task A: Map it (quick and clean)

In plain text, write:

• C: the main conclusion (one sentence)
• P1, P2, P3: the stated premises
• A1, A2: the most important unstated assumptions needed for the support to work

C: _____________________________  P1: ____________________________  P2: ____________________________  P3: ____________________________  A1 (assumption): _______________  A2 (assumption): _______________

Task B: Check whether the conclusion follows (focused evaluation)

Answer these questions in one or two sentences each:

• Support fit: Do the premises, if true, make the conclusion more likely?
• Support strength: Are the premises strong enough to justify the confidence level of the conclusion?
• Key vulnerability: Which assumption, if false, would most damage the argument?

Task C: Revise to make it clearer and more justified

Produce an “after” version that keeps the same topic but improves reasoning. Your revision must include all three moves:

• Precision: rewrite the conclusion to be specific (scope, action, timeframe, standard).
• Gap-filling: add at least one premise that directly bridges the main gap.
• Cleanup: remove at least one irrelevant or weak reason.

Optional upgrade (for extra rigor)

• Evidence upgrade: replace one vague claim with a measurable one (numbers, timeframe, comparison class).
• Qualification: adjust the conclusion to “probably,” “in these conditions,” or “pilot and measure.”
• Assumptions stated: add a sentence beginning with “This assumes that…”

Revision template you can copy

BEFORE (original excerpt): [paste]  MAP: C: ... P1: ... P2: ... A1: ...  EVALUATION: Fit: ... Strength: ... Vulnerability: ...  AFTER (revised argument, 3–6 sentences): ...