| name | s4h-logic-argument-validation |
| description | Check whether an argument's premises actually support its conclusion, and identify logical fallacies. Use when reviewing a design decision, technical proposal, product argument, or any reasoning where the conclusion needs to hold up under scrutiny. TRIGGERS: 'validate this argument', 'does this logic hold', 'check my reasoning', 'is this a fallacy', 'find the flaw in this', any proposal or decision where the reasoning chain matters. Pairs well with logic-consistency-check when a full document needs scrutiny. |
Logic Argument Validation
An argument can sound compelling while the reasoning is broken. Confident language, plausible premises, a conclusion that feels right — none of these guarantee the argument actually holds. This skill validates the structure: do the premises support the conclusion, and is the reasoning free of fallacies?
Your Process
Step 1: Extract the argument structure
Before evaluating, make the argument explicit:
- Premises: what claims is the argument built on?
- Conclusion: what is it trying to prove?
- Reasoning: what's the logical path from premises to conclusion?
Restate this clearly before proceeding. Often the weakest point becomes obvious once the structure is explicit.
Framing check: Confirm the argument being examined and the claim at stake before continuing. State what you've identified — the actual argument and the conclusion it is trying to establish — in one sentence, then use AskUserQuestion:
- Question: "I'm reading this as: [your one-sentence framing of the argument and its conclusion]. Is that right?"
- Header: "Framing"
- Options:
- Yes — proceed — framing is correct
- Adjust — one element is off; user will correct it before you continue
- Reframe — different situation than read; incorporate the correction before proceeding
Step 2: Test premise soundness
For each premise:
- Is it stated as fact? Is it actually established, assumed, or contested?
- Is it relevant to the conclusion, or is it doing rhetorical work without logical work?
- Are there hidden premises — unstated assumptions the argument silently depends on?
Step 3: Test the inference
Does the conclusion actually follow from the premises, even if the premises are true? Common inference failures:
- The premises support a weaker version of the conclusion than the one being claimed
- The reasoning jumps over a step that would need its own justification
- The conclusion is true but for reasons the premises don't establish
Step 4: Check for fallacies
Scan for common fallacies. Name them specifically if found:
| Fallacy | What it looks like |
|---|
| Ad hominem | Attacking the source rather than the argument |
| Straw man | Misrepresenting a position to make it easier to refute |
| False dichotomy | Presenting two options when more exist |
| Circular reasoning | The conclusion is smuggled into the premises |
| Slippery slope | Assuming a chain of consequences without justifying each step |
| Appeal to authority | Citing authority as a substitute for evidence |
| Hasty generalisation | Drawing broad conclusions from insufficient cases |
| Post hoc | Assuming causation from correlation or sequence |
| Equivocation | Using the same word in two different senses |
Step 5: Verdict
Human Check-in
Before proceeding, use the AskUserQuestion tool. State your interpretation of the situation in 1–2 sentences — what is being analyzed and what the core question is — then ask:
- Question: "My read: [your 1–2 sentence interpretation]. How do you want to proceed?"
- Header: "Scope"
- Options:
- Full analysis — Complete all steps, reasoning shown throughout
- Key findings only — Bottom-line output, skip step-by-step detail
- Validity test only — Skip premise truth assessment, test whether the conclusion follows from what's given
- Reframe — The read is off; correct it and the analysis will follow the corrected framing
Proceed based on their selection. If the user reframes, incorporate the correction before running any analysis.
Output Format
Argument:
[Premises / Conclusion restated explicitly]
Premise Assessment
| Premise | Status | Issue |
|---|
| [premise] | ✅ Established / ⚠️ Assumed / ❌ Contested | [note] |
Inference Assessment
[Does the conclusion follow? Where does the chain hold or break?]
Fallacies Detected
- [Fallacy name]: [specific example from the argument] — or "None detected"
Verdict
[Does the argument hold? What is the specific weakest point?]
What would strengthen it
- [Specific fix — evidence needed, premise to qualify, step to make explicit]
Notes
A broken argument isn't necessarily a wrong conclusion. The conclusion might be correct while the reasoning that supports it is flawed. Flag both: the structural problem and whether the conclusion still seems defensible by other means.
What's Next
After delivering this output, use AskUserQuestion to offer the next move:
- Question: "Argument validated. What's next?"
- Header: "Next"
- Options:
/s4h-logic-fixer — Repair the invalid inferences found/s4h-ethics-check — Check whether a valid argument is also ethically sound/s4h-communication-objection-mapping — Map how others will challenge this argument- Done — Wrap up and synthesise what we have so far
