Understanding what follows from “Whenever I go in the sun, I get a headache.” Decide which statement is logically entailed by this conditional, without assuming that I actually went in the sun today.
-
AI went in sun so I have headache now.
-
BI didn't go in sun so I don't have headache now.
-
CI m feeling headache that means I went in sun.
-
DNone of these
Answer
Correct Answer: None of these
Explanation
Introduction / Context:We analyze a everyday-language conditional: “If I go in the sun, then I get a headache.” Symbolically, Sun -> Headache. The question asks what we can conclude from this rule alone, without extra facts about today.
Given Data / Assumptions:
- Rule: Sun -> Headache (whenever antecedent holds, consequent follows).
- No assertion that I actually went in the sun.
- No assertion that I currently have or do not have a headache.
Concept / Approach:From a conditional P -> Q, we may infer Q if P happens (modus ponens). But unless we are told P is true, we cannot assert Q. Nor can we infer P from Q (that would be affirming the consequent). We also cannot infer not Q from not P (denying the antecedent).
Step-by-Step Solution:
1) Translate: P = “went in sun”; Q = “have headache”.2) The statement gives only P -> Q.3) To conclude Q now, we would need evidence that P is true now; none is given.4) To conclude not Q from not P is invalid.5) To conclude P from Q is also invalid.Verification / Alternative check:Construct scenarios: If I did not go in the sun but have a headache (for other reasons), the rule still holds. If I went in the sun and got a headache, it holds. The rule does not fix what happens when I do not go in the sun.
Why Other Options Are Wrong:
- “I went in sun so I have headache now.” Not supported; we are not told I went out.
- “I didn’t go in sun so I don’t have headache now.” Denying the antecedent—invalid.
- “I’m feeling headache so I went in sun.” Affirming the consequent—invalid.
Common Pitfalls:Confusing sufficient with necessary conditions. “Sun” is sufficient for “headache”, not necessary.
Final Answer:None of these.