It is simply a "non sequitur" because in 1. you talk about Jesus, in 2. you talk about the Church. Although there is a historical connection between the two, they are not identical or logically connected in a way that you can deduce from one to the other.
It is like
1. My father stayed out of politics
2. Therefore I should stay out of politics

But for this argument we are accepting the premise that "I should stay out of politics" as true.

Let's accept that premise. We can change the subject away from religion (for simplicity), and use an example of a student at school.

Teacher: "For your final essay, you can only choose any topic that belongs to Category A."
Subject X belongs to category B.
Therefore the student cannot write a paper on subject X

What the fallacy leaves out is that Subject X belongs to both categories and so while both premises are true, the conclusion is false. Is this still a non-sequitur?

I believe it is the Slippery slope fallacy.

This is when you start with A then though a series of steps (B, D...) you make equalize A and Z. The argument ends up being if A is true then Z must be true also.

Conclusions like these can be true but does not make it true.

Hmmm, I don't think it's a slippery slope, but I get what you are saying. To me it seems similar (but not identical) to the four terms fallacy.

I think it's the fallacy of exclusion? I just read about it.

First, "should/should not," "allowed/not allowed" and the like aren't going to be part of traditional logic. Those are normatives. You'd need some sort of well-developed system of deontic logic to deal with them, but even then, you're not going to be able to successfully move from a fact, such as "Jesus was/was not concerned with x" to any sort of normative implication, because of the is/ought problem. Any conclusion there would be a normative fallacy.

First, "should/should not," "allowed/not allowed" and the like aren't going to be part of traditional logic. — Terrapin Station

Logic does not concern itself with the meaning of the terms, and classical logic can perfectly well operate with moral premises and conclusions.

All terrapins are evil.
You are a terrapin.
Therefore you are evil.

A valid argument, though not necessarily true.

Group A should not engage in topic B.
Subject X is part of Topic B.
Therefore, Group A should not engage in Subject X — marshill

This, on the other hand would only be valid if part of topic B is topic B.

Which it isn't.

So part of driving a car is getting in the car, but just because I shouldn't drive the car (not having a licence) does not mean I shouldn't get in the car.

Here's something that marshill wrote:

Jesus was not concerned with politics
Therefore, the church should stay out of politics. — marshill

That's attempting to deduce a normative from a fact, no?

Sure, totally invalid - unless you add the premise that 'goes without saying' -"The church should emulate Jesus."

But of course Jesus so didn't stay out of politics, hanging out with tax collectors and overturning the tables of the moneychangers and all, so it's all tosh anyway.

[quote="marshill;d6018"
Group A should not engage in topic B.
Subject X is part of Topic B.
Therefore, Group A should not engage in Subject X

(Im failing to leave out the part that says Subject X is not only part of Topic B, but it is also part of Topic C, and that Group A is allowed to engage in topic C).[/quote]You have contradictory rules, that's your problem. It's not a fallacy, it's contradictory instructions.

You are not allowed to cross the street.
You are allowed to cross the street.

Any conclusion about crossing the street, that you are allowed, that you are not allowed is problematic, since you have been told opposite things.

The house is red.
The house is not red.
from those premises you cannot draw any conclusion.

Argument One:
Jesus was not concerned with politics
Therefore, the church should stay out of politics. — marshill

That's an incomplete argument. It is missing the premise that if Jesus is not interested in something, the church should not involve itself with it. Without that it is not possible to deduce the conclusion. And you will likely then need to demonstrate why that premise is true, many people are going to challenge it. But if that premise is true, the one that is missing, you are getting close to a valid conclusion. I don't think the missing premise is correct, but that's another story.

Argument Two:
As concluded in Argument one, the church should stay out of politics.
Abortion (or slavery, or any other moral issue) is a political issue
Therefore, the church should stay out of abortion. — marshill

This is close to a decent argument, if the premises are correct. But there is a real problem with the verb 'stay out'. What does it mean to stay out of abortion? In a sense it can be an equivocation. Stay out of politics could mean not supporting certain candidates, not punishing candidates, as an organization, on certain issues, and so on. What does stay out of abortion mean. A priest might say something about a political issue, but be staying out of politics. is saying the bible states that abortion is wrong, being political, or is it being theological? or both? or neither? We would need a very clear definition is for what staying out of entails, and since abortion and politics are not really in the same kind of category, what does it mean in both cases. Then we could look at the argument.

It seems to be that you're sneaking in a second premise in argument one, namely "The Church should try to act exactly as Jesus did". Only after assuming this can you claim that the church should stay out of politics.

I guess you could argue about the soundness of that hidden premise, but if you dont take it for granted, you cant make the jump to your conclusion in argument one.

Personally, I think that given the fundamental difference between the Church as an institution and Jesus as a person/divine being, there are things that the latter will be able to do that the former wont, and viceversa.

either C and B are coextensive or they are not. If they are co-extensive, then being allowed to talk about one while not being allowed to talk about other violates the rule of non-contradiction and your issue is not a matter of a fallacy. If C and B overlap, nowhere did you say that you can discuss anything and everything in C. Instead, you said you can discuss C. So your formulation reasonably implies that you can discuss those portions of C that do not overlap with B, which still means you can discuss C. If you say can discuss all of C and none of B, then you are back to the rule of non-contradictions and once again the issue is not a matter of a fallacy.

That would work if the church agreed with abortion being an exclusively political and not a religious and moral issue.



"For your final essay, you can only choose any topic that belongs to Category A."
Student can write a paper of subject X.

"For your final essay, you can choose any topic that belongs to only Category A."
Student cannot write a paper on subject X.



I don't know what exactly it's called but might I term it linguistic/grammatical fallacy? The "only" was in the wrong place in the sentence.

It's the fallacy of division: "A fallacy of division is the error in logic that occurs when one reasons that something that is true for a whole must also be true of all or some of its parts. "

Example:

Puritans should not engage in Satanic music.
Repetitive sounds are a part of Satanic music.

Therefore, Puritans should not engage with repetitive sounds.

Or,

Puritans should not engage in Satanic music.
Musical Instruments are used in Satanic music.

Therefore, Puritans should not engage in music that uses musical instruments.

:up: an even better example!

I think my mistake in this thread was I used too much complexity in my original post by including Jesus, religion, etc. Here is the simplification of the argument:

Teacher: "For your final essay, you can choose any topic that belongs to Category A."
Subject X belongs to category B.
Therefore the student cannot write a paper on subject X


This is a fallacy because subject X may also belong to Category A. I just didn't know the name of the fallacy. I still think its a fallacy of exclusion, but perhaps Vagabond is correct. :)

Here's an even better one:


Muslims should not eat pork.
All pork is meat.

Therefore Muslims should not eat meat.

Teacher: "For your final essay, you can choose any topic that belongs to Category A."
Subject X belongs to category B.
Therefore the student cannot write a paper on subject X — marshill

I would call thIs a fallacy of unwarrent assumption. IOW we have a premise that may or may not be true which is not stated. The above works if we have the additional premise that all topics in category B are not in Category A. So we have a missing premise or a false implicit premise. Now the above might be a valid conclusion if we know the two categories are not the same.

Teacher: you must choose a number that is a positive number.
A student cannot choose -7.

Teacher: you must choose a real number.
A student cannot choose -7.

And since your example is abstract. We don't know what the categories are, we don't know if it is a situation like my first example or like my second example.

It's also a bit like a fallacy of false dichotomy. Where it is as if we have two choices, when in fact there are more options.