Critical reasoning is gap logic: premise → unstated link →
conclusion, and then what to do next. Assumptions fill the past/present gap,
conclusions are what must follow, courses of action fix the future.
1. The Structure of an Argument — Anatomy
Premise → (unstated) Assumption → Conclusion. Remove the assumption and the chain breaks.
Part
Role
Example
Premise
Facts / evidence given
"All renewable energy sources are eco-friendly."
Assumption
Unstated link premise→conclusion
"Solar is renewable" (must be true for conclusion to follow)
Conclusion
Claim derived
"Therefore, solar power is eco-friendly."
2. Statements and Assumptions — The Missing Link
An assumption is not stated but must be true for the argument to hold. If false, the
argument collapses.
How to Identify
Gap strategy: find the missing link between premise and conclusion.
Example: "Govt should subsidize EVs because cost is a barrier." Gap: does cost actually stop
people? Assumption: high cost is indeed the main barrier.
Negation test (decisive): negate the candidate assumption — if the argument
now fails, it was the assumption. Statement "Free Wi-Fi in parks will boost
engagement." Negate candidate "People use Wi-Fi in public areas" → "People do NOT use Wi-Fi
in public" → argument fails → valid assumption.
Avoid extremes: assumptions are usually moderate. Words like "always, all,
never" are rarely assumptions unless the premise supports that strength.
Worked — Negation test: Statement: "Companies should offer remote work to
reduce attrition." Candidate assumption: "Employees value flexibility." Negate → "Employees do
NOT value flexibility" → then remote work wouldn't reduce attrition → argument collapses →
this is the assumption. Candidate "All employees prefer remote" is too extreme → not
the unstated link.
3. Statements and Conclusions — What Must Follow
A conclusion is a judgment that logically follows from the statement — directly
supported, no outside knowledge.
Rules
Stick to facts: "Carpooling reduced traffic" → "The program was effective"
is valid; "Carpooling is better than buses" is not (buses not mentioned).
Key indicators: "therefore, thus, hence, implies" signal conclusions.
Validity vs truth: a conclusion is valid if it logically follows, even if
the premise is factually wrong in the real world.
No generalization: "remote learning for self-paced subjects" → don't
conclude "All students prefer remote learning" (scope broadened).
4. Courses of Action — What Should We Do Next?
A course of action is a step/administrative decision for improvement, follow-up, or further
action.
Criteria for a Valid Course
Criterion
Test
Example
Solves the problem
Directly addresses core issue?
Water contaminated → provide alternative water ✓ vs blame industry ✗
Feasible / practical
Realistic to implement?
Traffic high → improve public transport ✓ vs ban all cars ✗
Balanced
Doesn't create a bigger problem?
Defect rate ↑ → improve QC ✓ vs cut benefits ✗
Also: ensure the action targets the cause (outdated machinery → modernize machinery),
not just the symptom.
All three filters must pass. Failing any one → reject the course of action.
5. Comparison of Question Types
Type
Focus
Key Question
Assumption
Missing link (past/present)
"What must be true for this to make sense?"
Conclusion
Result (present)
"What logically follows from this data?"
Course of Action
Solution (future)
"What should we do next to fix this?"
6. Strategic Solving Tips
Identify type first: read the stem — hidden premise (assumption), logical
result (conclusion), or solution (course). The same statement leads to different answers per
type.
Eliminate irrelevants: in "Online Shopping" example, "Physical stores are
obsolete" is too extreme; "Convenience is driving the decline" is nuanced and matches
premises.
Cause → effect: in course-of-action, target the cause (e.g.,
outdated machinery → costs → modernize), not the effect alone.
Unstated link premise→conclusion is?
Negate candidate: argument fails → candidate is?
Assumptions are usually?
Conclusion must be?
Valid course of action must NOT be?
Which targets cause? Outdated machinery → high costs.
Assumption vs Conclusion: “What must be true for this to make sense?”
Target cause, not symptom (eg machinery → modernize)
Types :-
Assumption ⇒ missing link (What must be true?) ; Conclusion ⇒ result (What
follows?) ; Course ⇒ solution (What to do?)
Primary source: none pinned yet — drop your preferred video/book resource into
RESOURCES.md and it will be linked here. Ask me anything that's
unclear.