Logic puzzle: deductive entailment

[public hermit]

Assume the following:

1. A is a Christian
2. A and B are friends
3. B and C are friends
4. C is not a Christian

Does it follow from these facts that there is at least one Christian with a non-Christian friend? Yes or No?

 

[NerdGirl]

Since it's not established that A and C are friends, no.

 

[Of the Kingdom]

Assuming, as Aristotle did, that either "B is Christian" or "B is not Christian", yes.

 

[honey badger]

to apply logic you can not have an unknown element ...

 

[public hermit]

to apply logic you can not have an unknown element ...

You only have two pertinent options for B.

 

[Sparagmos]

Since it's not established that A and C are friends, no.

Whether B is or isn’t a Christian, ypu end up with a pair where one is not a Christian.

 

[NerdGirl]

The question is "is there a Christian with at least one non-Christian friend".
The only established Christian in the group is A.
The only established non-Christian in the group is C.
There is no direct connection established between A and C.

 

[NerdGirl]

Whether B is or isn’t a Christian, ypu end up with a pair where one is not a Christian.

I do believe you've solved it.