"All dogs are animals. All cats are animals. Therefore all dogs are cats." — hearing this, Karan…
"All dogs are animals. All cats are animals. Therefore all dogs are cats." — hearing this, Karan thinks this reasoning is correct, since both starting sentences are true. His sister says the conclusion is wrong even though both sentences are true. Who is right?
Who do you think is right? Pick one.
The answer: His sister is right, the conclusion is wrong even though both sentences are true
Why
Karan is assuming that if both starting facts are true, any conclusion drawn from them must also be true — but true statements can still be combined in an invalid way. Both 'dogs are animals' and 'cats are animals' place dogs and cats inside the same larger group (animals), without saying anything about whether dogs and cats overlap with EACH OTHER — sharing a category with something is not the same as being connected to everything else in that category. Test it directly: dogs really are animals, cats really are animals, and dogs are definitely not cats — a real-world case where both starting sentences hold completely true, yet the conclusion is false, which alone proves the reasoning pattern itself is broken, regardless of which specific words are used. His sister is right: 'All A are C, all B are C, therefore all A are B' is not a valid pattern of reasoning — sharing one group in common does not connect two things to each other.
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