#10 - All material bodies are divisible into parts, and

[srcline@noctrl.edu]

Hello,

So I think i diagrammed this right but, I wanted to make sure, but I still don't understand how to link these together. This is a MBT question correct? But I dont know what the inference is with this one. If somone can also please explain why E is wrong and the correct answer is D , that would greatly be appreciated.

MB DIP I
MB I
S (not) MB

This is as far as I got.

Thankyou
Sarah

[Emily Haney-Caron]

Hi Sarah,

This is a justify the conclusion question with conditional logic. You have the diagramming of the question right, and I think the place you got stuck is in not taking the contrapositives. I MB
Not imperfect is the same as perfect, because of the double negative. So, we have some reason to know the spirit is not a material body. The reason here must be connected to that contrapositive - the spirit must be perfect. It also follows that if the spirit is perfect, it is also indivisible. The problem with E is that it says EITHER, when it would have to be BOTH. Does that help?

[srcline@noctrl.edu]

Hello Emily,

Why would I have to take the contra Postive of MB I?

Thankyou
Sarah

[Clay Cooper]

Hi Sarah,

In short, you always have to consider the contrapositive, of each and every conditional rule you encounter. Actually, the conditional rule itself is really made up of its original form and its contrapositive; they are essentially indistinguishable, even if we tend to diagram them and think of them separately.

The test-makers consistently create questions that require you to consider the contrapositive of a conditional rule in order to find the correct answer, so I would encourage you to make a habit of immediately and automatically diagramming the contrapositive of every rule you diagram.

I have seen from some of your other posts that you are more than capable of finding the contrapositive, even of complicated rules with more than one term on one side of the arrow; that is a skill with which many students struggle, but you seem to have it down. I can assure you, from experience, that if you make a habit of doing it every time you encounter a conditional rule, it will pay off.

[nwang121]

Hi,

I'm still confused about this question. If Spirit --> not material and perfect --> not material, there's no way to connect spirit and perfect, correct? Since any way to connect these two would need mistaken reversal/mistaken negation?

[Rachael Wilkenfeld]

Hi nwang121,

Our stimulus tells us that all material bodies are imperfect. MB P. We can take the contrapositive of that and say P MB. The stimulus concludes that the spirit is not a material body.

What do we know that would be sufficient to tell us something is not a material body? If it was perfect. That's the contrapositive of the conditional reasoning at the start. So answer choice (D), which tells us that the spirit is perfect is sufficient for us to conclude that the spirit is not a material body. There's no mistaken negation/reversal issue--the answer choice fits right into our contrapositive.

Hope that helps!
Rachael

[ericj_williams]

Hi Sarah,

This is a justify the conclusion question with conditional logic. You have the diagramming of the question right, and I think the place you got stuck is in not taking the contrapositives. I MB
Not imperfect is the same as perfect, because of the double negative. So, we have some reason to know the spirit is not a material body. The reason here must be connected to that contrapositive - the spirit must be perfect. It also follows that if the spirit is perfect, it is also indivisible. The problem with E is that it says EITHER, when it would have to be BOTH. Does that help?

Aren't there times though a double-negative does not imply the opposite?

I feel like there are times in which a binary situation is not always created with a double-negative. Is this possible?

I can't think of an example but I feel like on the test it has tried to trick test takers by using a double-negative and then creating a possible third option overlooked.

[Ryan Twomey]

Hey Eric!

I would not describe a double negative as implying the opposite. You could describe it as the logical opposite. I would describe it as canceling each other out or as negating each other. So the instructor Emily was correct when describing "not imperfect" as "perfect".

I cannot think of any examples where a double negative does not cancel each other out.

The assumption here after mapping out all of the conditional logic is: spirit--------> not imperfect, which just means that we are looking for spirit------->perfect

There is a difference between a logical opposite and an opposite. Here is an example: the logical opposite of "all" is" not all": aka the negation of "all" is "not all". It would be incorrect to say the logical opposite of "all" is "none."

Double negatives always cancel each other out. So if I were to say: "it is false that it is not going to rain tomorrow. "That statement would translate to "it is going to rain tomorrow."

I hope all this helps you!

Best,
Ryan