Is it an example of affirming the consequent?
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Original Question
I'll have my reporting for hypothetical proposition in my class, and I kinda, don't understand yet about the difference between Affirming the consequent and denying the antecedent
In the example statements below.
Premise 1: If Rex is a dog, then rex is an animal.
Premise 2: Rex is an animal
Conclusion: Therefore, Rex is a dog.
Explanation: premise 2 is the basis of conclusion and, in the statement "Rex is an animal" The conclusion is "rex is a dog". It is an invalid argument because Rex may be a cat, or any animal it may be.
It is an example of affirming the consequent?
Is my explanation is correct?
What does affirming the consequent means? ( in more simple definition please)
In the example statements below.
Premise 1: If Rex is a dog, then rex is an animal.
Premise 2: Rex is an animal
Conclusion: Therefore, Rex is a dog.
Explanation: premise 2 is the basis of conclusion and, in the statement "Rex is an animal" The conclusion is "rex is a dog". It is an invalid argument because Rex may be a cat, or any animal it may be.
It is an example of affirming the consequent?
Is my explanation is correct?
What does affirming the consequent means? ( in more simple definition please)
Answers
3Yes, I think you have it on the nose, so to speak.
The point of affirming the consequent in this case is that there is more than one way for a creature to be an animal. Being a dog is one way, but it is possible to be an animal by being a cat, a lizard, a ladybug, etc. That's why the argument is faulty. "If Fuzzy is a dog, Fuzzy is an animal. Fuzzy is an animal, so Fuzzy is a dog." But - oops - Fuzzy is a kitten! Premises are both true, but the conclusion is wrong.
Denying the consquent works, however. Imagine that Fuzzy is a stuffed plush sofa pillow. Like this: "If Fuzzy is a dog, Fuzzy is an animal. Fuzzy is not an animal, so Fuzzy is a not a dog." That is a valid, sound argument.
Affirming the consequent is a common fallacy. Politicians use it every day.
The point of affirming the consequent in this case is that there is more than one way for a creature to be an animal. Being a dog is one way, but it is possible to be an animal by being a cat, a lizard, a ladybug, etc. That's why the argument is faulty. "If Fuzzy is a dog, Fuzzy is an animal. Fuzzy is an animal, so Fuzzy is a dog." But - oops - Fuzzy is a kitten! Premises are both true, but the conclusion is wrong.
Denying the consquent works, however. Imagine that Fuzzy is a stuffed plush sofa pillow. Like this: "If Fuzzy is a dog, Fuzzy is an animal. Fuzzy is not an animal, so Fuzzy is a not a dog." That is a valid, sound argument.
Affirming the consequent is a common fallacy. Politicians use it every day.
Yes you are correct....proper form is
If (p) rex is a dog, then (q) rex is an animal
(p) rex is a dog
(q) rex is an animal
Affirming the consequent is to switch the P in the second line with the Q. Modus Ponens means mode to affirm by affirming. So, affirming the consequent would mean "affirming the Q", i.e. Affirming it in line two BEFORE you used P, the conditional, in line two to do so.
If (p) rex is a dog, then (q) rex is an animal
(p) rex is a dog
(q) rex is an animal
Affirming the consequent is to switch the P in the second line with the Q. Modus Ponens means mode to affirm by affirming. So, affirming the consequent would mean "affirming the Q", i.e. Affirming it in line two BEFORE you used P, the conditional, in line two to do so.
You've got it exactly.
Meanwhile, Denying the Antecedent would be a different error of the form
If P then Q.
Not P
Therefore not Q
Or, in your example:
Premise 1: If Rex is a dog, then rex is an animal.
Premise 2: Rex is not a dog
Conclusion: Therefore, Rex is not an animal.
Of course, as before, Rex could be a kitten. Or a Tyrannosaur.
Meanwhile, Denying the Antecedent would be a different error of the form
If P then Q.
Not P
Therefore not Q
Or, in your example:
Premise 1: If Rex is a dog, then rex is an animal.
Premise 2: Rex is not a dog
Conclusion: Therefore, Rex is not an animal.
Of course, as before, Rex could be a kitten. Or a Tyrannosaur.
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