• It is not valid. In this two possible are as true and false that's why it's is not valid.

  • Hi Babai,

    I don't think it is valid. Here is my explanation.

    First premise: All roses are flowers --> All of A is B

    Second premise: Some flowers fade quickly --> Some of B is C

    This means that some of A is unclear whether it includes some of B or not. It can be D, E, F, or else. Some flowers in second premise are not certainly roses.

    There is no strong connection between first and second premise. Therefore, we cannot say that some of A is C. We cannot say that some of roses fade quickly. This is an invalid conclusion.

    Let me give similar situation....

       All elephants are animals.

       Some of animals can run fast.

       Therefore some elephants can run fast. 

    --> This is also invalid syllogism.

    • Excellent reasoning. Although it's obvious that the syllogism doesn't look right, reasoning it step by step is not easy.

    • Yes, exactly.

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