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Sergiu

Are the following syllogisms valid or invalid?

All women are feminists
Some bankers are women
Therefore, some bankers are feminists.

No comets are cosmic objects
Some planets are not cosmic objects
Therefore, some planets are not comets.

All tigers are felines
All tigers are animals
Therefore, all animals are felines.

All critical thinkers are atheists
No Christians are atheists
Therefore, no Christians are critical thinkers.

Some philosophers are intelligent
Some women are not philosophers
Therefore, some women are not intelligent.





asked on Tuesday, Aug 11, 2015 07:58:30 PM by Sergiu

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Answers

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mike
0
Valid
Valid
Invalid
Invalid
Valid
answered on Wednesday, Aug 12, 2015 12:19:18 AM by mike

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michael
0
1) Valid, The some bankers that are female are feminists
2) (Invalid?) I'll posed (unclear), if by some you mean 1 or more but not all, then it is valid. The cosmic planets are not comets. If some can include possibly all then all planets could be not cosmic and all planet could be comets ( Affirmative Conclusions from a Negative Premiss)
3) Invalid, (Undistributed middle term.)
4) Valid, assuming that christians and atheists are mutually exclusive groups. All critical thinkers are contained in Atheist, leaving none to be christain.
5) Invalid, some philosphers being intelligent does not exclude the possibility that non philosphers can be intelligent, there is nothing preventing the non philospher women from being entirely within the group of intelligent people.
answered on Saturday, Aug 15, 2015 04:23:01 PM by michael

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michael
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The first one is okay. The rest have problems.
The second gets the result right but the premises are wrong.
The third and fourth are non-sequiturs since the conclusion does not follow from the arguments. There are some Christians who do think critically and some atheists who do not.
The fifth has the same problem as the second; there can be stupid philosophers and non-stupid non-philosophers.
answered on Monday, Aug 17, 2015 05:54:35 PM by michael

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michael
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Remember, valid merely means form, it has nothing to do with whether the thoughts are reasonable. It's obvious that all critical thinkers are not atheists. But within the form of the syllogism, valid doesn't reflect the definition of valid out in the real world, It merely means form of the arguemnt. The argument isn't sound, which means its basically hot air. People who use this type of argumentation then claim valid aren't actually in need of discussion they merely try to promote personal opinion. I could have sworn that there is a personal opinion fallacy syllogism. But I'm not sure.
answered on Wednesday, Sep 16, 2015 05:02:26 PM by michael

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Do.C
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Remember, valid merely means form, it has nothing to do with whether the thoughts are reasonable. It's obvious that all critical thinkers are not atheists. But within the form of the syllogism, valid doesn't reflect the definition of valid out in the real world, It merely means form of the arguemnt. The argument isn't sound, which means its basically hot air. People who use this type of argumentation then claim valid aren't actually in need of discussion they merely try to promote personal opinion. I could have sworn that there is a personal opinion fallacy syllogism. But I'm not sure.
answered on Tuesday, Jan 18, 2022 07:42:46 PM by Do.C

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