In this syllogism question, two statements are given about birds, trees and hens. Treat both statements as true and decide which of the conclusions, if any, logically follow: Statements: (I) All birds are trees. (II) Some trees are hens. Conclusions: (I) Some birds are hens. (II) Some hens are trees.

Difficulty: Medium

Correct Answer: Conclusion II follows

Explanation:


Introduction / Context:
This question presents a deliberately unrealistic set relation among birds, trees and hens to focus purely on logical structure. You must treat the statements as literal set relations and decide which of the two conclusions are logically forced when those statements are true.


Given Data / Assumptions:

  • Statement I: All birds are trees.
  • Statement II: Some trees are hens.
  • Conclusion I: Some birds are hens.
  • Conclusion II: Some hens are trees.
  • We ignore real world biology and accept the statements as abstract set relations.


Concept / Approach:
All birds are trees means the entire set birds lies within the set trees. Some trees are hens means that there is a non empty intersection between the sets trees and hens. From this, we can decide whether there must be an overlap between birds and hens (conclusion I) and whether there must be hens that are trees (conclusion II). A conclusion follows only if there is no way for the statements to be true and that conclusion false at the same time.


Step-by-Step Solution:
Step 1: Translate statement I into set form: birds ⊂ trees. Every bird is a kind of tree. Step 2: Translate statement II: some trees are hens. So the intersection of trees and hens is non empty. Step 3: Consider conclusion II first. Some hens are trees is simply another way of stating that some trees are hens. These two statements are logically equivalent; they describe the same overlap from different directions. Step 4: Therefore conclusion II must follow from statement II. Step 5: Now examine conclusion I: some birds are hens. For this to be forced, the intersection of birds and hens would have to be non empty in every model that satisfies the statements. Step 6: The statements do not say that the particular trees which are hens are also birds. The hens that are trees might all lie in the part of trees that does not contain birds. Step 7: So it is possible that birds form one subset of trees, hens form another overlapping subset of trees, and these two subsets do not overlap at all. In that case, some birds are hens would be false while both statements remain true.


Verification / Alternative check:
Construct a simple diagram. Let trees be {t1, t2}, birds be {t1} and hens be {t2}. Then all birds (t1) are trees, so statement I holds. Some trees (t2) are hens, so statement II holds. However, there is no element that is both a bird and a hen, so conclusion I fails. At the same time, some hens (t2) are trees, so conclusion II is true. This shows that conclusion II follows but conclusion I does not.


Why Other Options Are Wrong:
Option A selects conclusion I, which is not forced since a counterexample exists. Option C says neither conclusion follows, but conclusion II follows directly from statement II. Option D says both follow, which is too strong. Option E suggests that exactly one of the two follows without specifying which, but the question format expects you to identify conclusion II explicitly as the correct one.


Common Pitfalls:
A frequent mistake is to assume that if two sets both lie partly inside a third set, then they must overlap each other. This is not necessarily true: two disjoint circles can both lie inside a larger circle. Another pitfall is to overlook that some trees are hens is logically identical to some hens are trees, but does not say anything about birds directly.


Final Answer:
The correct logical assessment is that only conclusion II follows from the given statements.

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