Is there anyone here who is good with Symbolic Logic? Here's a challenge..

[truth2power]

Yesterday (Tues.) afternoon between about 1 and 3 pm there was a full-hour show on NPR about Mel and Norma Gabler. You all probably remember them; they're the Texas couple who campaigned against public school textbooks back in the 60's, calling the books "anti-Christian".

During the show there was a short clip of a Sunday School teacher who was telling his students that he would prove, logically, that God exists. I thought, "This should be good." He then said:

Either Jesus is God or he is a bad man. (I assume he was using the exclusive "or&quot
Jesus is not a bad man.
Therefore, Jesus is God.

Well, this is a pantload! But can someone explain where the flaw is in terms of symbolic logic? I'm thinking it's the premise, somehow.

I guess I should say that I'm fascinated by this stuff, but I would never take a logic course because I'd surely fail. Also, it makes my head hurt.

Thanks for any input.

[Coyotl]

1. Begin with a false assumption .....

Proving the false assumption to be false does not make the other half of the also false choice true.

Either Jesus is God or he is a man.
Jesus is not god since there are no gods.
Jesus is therefore just another man, albeit the Romans think he is a real asshole.

[kelliekat44]

59. Either I am a bad person or I am god. WTF? nt

[Vox Moi]

2. False Premise but logically valid

Which is the trouble with most religions

[2banon]

11. logically valid?

I don't get that at all.

but following the logic of the quote in the OP... If Jesus is good then he must be God, or if he isn't Good, then he's a bad man.

Well we all know what a loving and good creature Jesus was, so following the logic would suggest or imply that all of us are God. Except for those evil bad people, the rest of us good folks are God.

That just about sums it up, I think. and it certainly works for me.

I am Good, therefore I am God. And so are You!!

Except when I'm not good, then I guess I'm the devil, until I'm good again.

[immoderate]

14. Not so fast.

The premise is not logical. It violates the "rule of the excluded middle" resulting in a false dichotomy.

--imm

[Vox Moi]

23. I mean that sound logic can be applied to a false premise

In the example under discussion:
IF the premise is true, the conclusion is true.
If the premise is false, the conclusion is false.
But the conclusion is the same, either way.
So, the process of reasoning - logic - is independent of the validity of the premise.
Kinda like using sound mathematical procedures to add apples and oranges.

No sure how to express this idea in proper logical terminology. Help?

[immoderate]

24. The problem is that the original premise contains a fallacy. It is not valid or sound.

http://en.wikipedia.org/wiki/Law_of_excluded_middle

I don't see how a valid conclusion can result from a false premise. It might be a valid statement, but not as a result.

--imm

[Vox Moi]

41. Fishwax - Poster #15 - is working the same idea

Hey Immoderate:
Please forgive an overwrought reply but this stuff is fun.

Yes, I think I see what you mean: the whole syllogism is illogical if the premise is unsound. My saying 'logically valid' is not technically right since the premise is part the logic.

What I was thinking was something more iike the mistake of adding 2 apples and 2 oranges. You can add the numbers and get a result. The trouble is not in the process of addition (2+2=4) but in ignoring the issue of units.
So, the process of addition seems to be done correctly (some might say logically) - but the conclusion is invalid. That's the hair I was trying to split in saying that a 'logical' inference can be made regardless of the truth of the premise.

Technically, I think you are entirely right and my statement needs enhancement.
The inference is 'logically valid' and everyone who believes that 2+2 =4 would agree.

Being over-stuffed is in season so I won't apologize for all this and instead wish you and yours a happy Thanksgiving.

[immoderate]

56. Fishwax set me straight. We're all friends here.

--imm

[MineralMan]

3. The premise is faulty.

The entire thing collapses on that basis.

[arcane1]

4. A pantload indeed!

http://en.wikipedia.org/wiki/False_dichotomy

[antigone382]

5. It assumes that because the gospels attribute to Jesus claims of divinity...

He is either a liar (and therefore a bad man) or he is telling the truth (and therefore God).

I've seen other fallacious logical exercises that have the same dichotomy, with the added option that Jesus was crazy. They then prove that because Jesus did or said this or that (again, according to the Gospels) he could not be crazy or a liar. So therefore he's God.

What's missing is honest admission that the earliest Gospel in the Bible was written somewhere around 35 years after Jesus is thought to have died, and that each of the gospels was written with its own political and religious agenda, and its own intended audience. While the gospels converge on several points (particularly Matthew, Mark, and Luke, which seem to have been written in succession), there are also several points at which their timelines and theological points conflict. There is no way to verify that any particular statement attributed to Jesus was actually said by him. Therefore a supposed assertion by Jesus that he is God does not necessarily stand or fall based on the other statements and actions of Jesus as described in the gospels.

This doesn't even get into the fallacious reasoning that a person who is dishonest or delusional in some aspects of his or her life must not have great integrity or wisdom in other aspects.

[Egalitarian Thug]

6. All authoritarian arguments are rooted in a false premise, and this one is an easy example.

Give any of them a few minutes to make their case and they will get around to each logical fallacy, eventually.

[immoderate]

7. The first sentence violates "the law of the excluded middle."

You could logically say "Jesus is god, or he is not god." The implication here is that not being god means the same thing as being a bad man.

It is a false dichotomy, because it ignores the other possible implications, such as Jesus was a good, but ordinary guy, or that he never was.

--imm

[RKP5637]

12. +1, n/t

[EOTE]

8. Christ, where to start?

You're right, it is the premise. As mentioned above, you're starting with a couple of false assumptions. Also, a false dilemma. Nothing in the premise of this argument can be taken to be true in and of itself, so the argument is worthless. I'd go into it further, but I really can't imagine anyone making such an idiotic argument is going to be amenable toward following a Socratic debate.

[RKP5637]

9. The premise is ridiculous and hence the contrived result. n/t

[lapfog_1]

10. false premise AND possibly false assertion

"Jesus in not a bad man."

Not proven.

Jesus may have been a very bad man by convincing the world that he was a "good man" (while pretending to be the son of god).

[FatBuddy]

13. Love is blind

Ray Charles is blind
Therefore, Ray Charles is love

[riqster]

26. Now, that is logic!

[hootinholler]

39. But Stevie Wonder!

Splain that!

[fishwax]

15. it's a valid argument, but that doesn't make it sound

An argument is valid if it is structured such that if the premises are true then the conclusion must be true. The argument structure he's used is valid.If an argument is valid and the premises are true, then the argument is sound, and the conclusion must be true.

But validity implies nothing about the truth of the premises. Here is an argument with the exact same structure:

Either Jesus is a cereal box or he is a monkey wrench.
Jesus is not a monkey wrench.
Therefore, Jesus is a cereal box.

The argument is valid. But that doesn't really prove that Jesus is a cereal box.

[immoderate]

19. Logic police here: NO! It violates the "law of the excluded middle."

http://en.wikipedia.org/wiki/Law_of_excluded_middle

It creates a false dichotomy.

--imm

[fishwax]

25. The first premise is flawed, to be sure, but that doesn't change the validity of the argument

I don't dispute that the first premise is a false dichotomy. (To be picky, it is a fallacy of the excluded middle--another term for false dilemma/dichotomy--rather than violating the law of the excluded middle, which says that with a given proposition either the proposition or ots negation must be true.)

But validity is about structure, and the structure of the argument (a or b; not b; therefore a) is valid.

[immoderate]

34. OK, I get you.

Structurally, the argument is valid even if the statements are nonsense.

But, stepping back, I can't say the conclusion is "logical."

--imm

[Vox Moi]

60. Thanks, Fishwax

[Tierra_y_Libertad]

16. Jesus is either a can of tuna or a bad man.

Jesus is not a bad man.
Therefore, Jesus is a can of tuna.

[longship]

30. Is this a comment on transubstantiation?

Yummy! Jesus... er eh... tuna sandwiches for lunch today.

[Tierra_y_Libertad]

31. At least it wouldn't be cannibalism....unless those indulging are also tuna.

[Pretzel_Warrior]

17. You can apply a second logical tautology showing Person A is not a bad man and is not God

Person A is not a bad man.
Person A is not God.

Therefore, one could derive a statement from the two that Not being bad man is a necessary but insufficient requirement for "being God".

[postulater]

18. I like it better this way.

Either I am God or I am a bad man.
I am not a bad man.
Therefore, I am God.

So kneel down, heathens!!!

[riqster]

27. Then you don't know what it's like to be the bad man, to be the sad man.

I have it on good authority that nobody knows.

[postulater]

50. You're right. I have brown eyes.

[riqster]

51. Excellent.

[mynaturalrights]

20. Where to begin but it has already been answered

by the other members.

I'll just file this with the undeniable proof of existence in god with the banana premise.

[valerief]

21. Faulty premise. Ain't no god. nt

[upaloopa]

22. Everything relys on the first premice which needs proof before

it can be used as proof of something it is supposed to support.

[longship]

28. There's a bit of begging the question, too.

Begging the question, not in the casual sense of the phrase's use, which I always phrase as "invites the question", but in the more formal logical argument sense, where it means assuming the conclusion in the premise.

The argument here is indeed a classic case of excluded middle, but it also touches on begging the question because the argument is set up such that it presents a choice, either Jesus was God or was bad, that no believer would choose the latter. That's begging the question.

I agree with Immoderate, the primary fallacy is "the excluded middle" "false dichotomy" in the premise which makes the entire argument fallacious.

Happy to respond to fun stuff like this.
R&K

[Rex]

29. It is a trick question, logic cannot be used to prove or dissprove faith.

The 'either, or' argument is invalidated by the subject. Faith is the opposite of empiricism. Logic lives in the natural world.

[longship]

33. Tell that to William Lane Craig.

He loves this kind of stuff. And his logic always ends up with God exists, Jesus is God, hallelujah! Typical apologetics.

[Rex]

35. By his logic

Evil Spock was good.

[FiveGoodMen]

42. Evil Spock was ALMOST good

He was better than anyone else in his world and the best hope for that dimension at the end of the episode.

(none of which affects the OP's subject)

[Rex]

46. Well then Jesus was ALMOST God.

That proves it! Thanks guys, I knew we could sort this out.

[JVS]

57. If evil Spock is almost good, does that mean good Spock is nearly evil?

Or does it mean that Spock's sense of order and ability to understand the situation is inherently good whether possessed by a good Spock or an evil counterpart?

[FiveGoodMen]

70. The latter

Because he responds to reason, rather than emotion, he can see the usefulness of cooperation and honorable behavior no matter what cultural norms surround him.

For my money, it was the show saying that reason is the way we raise ourselves up.

[Cleita]

32. Where to begin.

The first premise is false. No one can prove that Jesus existed let alone that he was either good or bad. I mean according to the gospels, the Romans thought he was a bad man. That's why they crucified him. Also there are a few more premises missing as to what one would consider a god. Your whole argument is a proof worthy of Sarah Palin.

Actually there is a far more elegant argument on I believe eight proofs of the existence of god. There is an equally elegant argument of eight proofs against the existence of god? take your pick. If you pick the argument for the existence of god, then you have a premise.

You can say god is all seeing, all present immortal etc. Then if you can say that Jesus is all seeing, all present, immortal etc. then you can say, therefore Jesus is God.

But the rub is proving the existence of god and his attributes and the existence of Jesus and his attributes before you can reach a logical conclusion.

[Aerows]

36. If that's logic

I'm either a mainframe or a human being.
Mainframes are capable of logic
I must be a mainframe computer.

[Dan de Lyons]

37. In the real world there is no "either/or"

The structure of the initial assumption - not the initial assumption itself - guaranteed an illogical conclusion.

Jesus could have been God being a bad man. Jesus could have been a bad man pretending to be God. Jesus could have been God pretending to be a bad man pretending to be God.

Forcing a binary choice leaves reality behind.

"In Him there is no East or West, in Him no South or North... but one great fellowship of love, throughout the whole wide earth." ~ Oremus Hymnal.

[ithinkmyliverhurts]

38. "In the real world there is no "either/or""

Yes there is. Of course there is.

[struggle4progress]

40. That's called disjunctive syllogism: it's generally been considered a valid argument form

since the time of the ancient Greeks, and it doesn't require exclusive "or"

You probably use it all the time:

Either Fred is in the copy room or he has gone to lunch
Fred is not in the copy room
Therefore: he has gone to lunch

[Dan de Lyons]

45. Is the intial premise a complete statement of all the real possibilities?

In the real world, Fred may have passed out on the floor in the hallway. Had a stroke. The set of possibilities is infinite, some of them more probable than others.

If you are satisfied with initial premises that do not effectively describe the set of possibilities or at least the range of the set, your results may be not as accurate as you had hoped.

[struggle4progress]

47. I merely said it's considered a valid argument form: I made no claim about the truth

of falsity of the particular premises here

[seveneyes]

43. God is not an agreed upon fact. Logic requires fact to function

Emotional Logic is not universal among all humans.

[Sheepshank]

44. Boy oh boy.....

Either Jesus is God or he is a bad man. (I assume he was using the exclusive "or&quot
Jesus is not a bad man.
Therefore, Jesus is God.

I think that what is really happening here is the bigger more global explanation that since I am not a bad man (good thing for being a woman), I am therefore a God.

I *knew* it!!

[Sivafae]

48. This is an excellent example of a "Forced Dichotomy or Dilemma"

This is actually an excellent example of what is termed a "Forced Dichotomy." It is the same as Bush's famous, "You are either with us or against us."

The logic is that neither of the two claims can be logically proven in of themselves and they are the only choices given to make the final statement true. Especially since the two assertions/claims are given as opposites and are not truly opposite. You can be the son of god and a bad man.

more at link:

http://en.wikipedia.org/wiki/False_dilemma

[Tikki]

52. Where does boosh's 'they hate us for our freedoms' fall?…seems to me it was never logically...

strong.


Tikki

[FiveGoodMen]

72. What Bush said was worse

Although it revolves around the same failed logic, what Bush said was worse than "with us or against us".

He said you're either with us or with the terrorists. (not just "against us&quot

It was very similar to, "you either believe MY version of religion or justly deserve the hell you're going to."

[Agnosticsherbet]

53. It appears to be a use of False Dichotomy

It sets up two choices and then eliminates one without any logical reason

The argument neglects to mention that there is a possibility of more than two choices.
(1) Jesus could be a good man, but deluded.
(2) Jesus could be a good man but the statements reported in scripture were not translated properly.
(3) Jesus might not have existed.

There are many others. It is set up that you absolutely accept the biblical account as accurate. It is not an either/or choice.

False Dichotomy

False dichotomy
Definition: In false dichotomy, the arguer sets up the situation so it looks like there are only two choices. The arguer then eliminates one of the choices, so it seems that we are left with only one option: the one the arguer wanted us to pick in the first place. But often there are really many different options, not just two—and if we thought about them all, we might not be so quick to pick the one the arguer recommends.

Example: “Caldwell Hall is in bad shape. Either we tear it down and put up a new building, or we continue to risk students’ safety. Obviously we shouldn’t risk anyone’s safety, so we must tear the building down.” The argument neglects to mention the possibility that we might repair the building or find some way to protect students from the risks in question—for example, if only a few rooms are in bad shape, perhaps we shouldn’t hold classes in those rooms.

Tip: Examine your own arguments: if you’re saying that we have to choose between just two options, is that really so? Or are there other alternatives you haven’t mentioned? If there are other alternatives, don’t just ignore them—explain why they, too, should be ruled out. Although there’s no formal name for it, assuming that there are only three options, four options, etc. when really there are more is similar to false dichotomy and should also be avoided.

[Agnosticsherbet]

54. This also falls under the logical fallacy "begging the question"

The argument asks the reader to accept the conclusion without providing real evidence.

Begging the question
Definition: A complicated fallacy; it comes in several forms and can be harder to detect than many of the other fallacies we’ve discussed. Basically, an argument that begs the question asks the reader to simply accept the conclusion without providing real evidence; the argument either relies on a premise that says the same thing as the conclusion (which you might hear referred to as “being circular” or “circular reasoning”), or simply ignores an important (but questionable) assumption that the argument rests on. Sometimes people use the phrase “beg the question” as a sort of general criticism of arguments, to mean that an arguer hasn’t given very good reasons for a conclusion, but that’s not the meaning we’re going to discuss here.

[RagAss]

58. No God. No good or bad. Concepts. All human concepts.

That was easy.

[Warren DeMontague]

61. Either I am a banana or I am on an airplane.

I am not, currently, on an airplane.

Therefore, I am a banana.

[bananas]

62. Therefore, you're all my sockpuppets. nt

[Warren DeMontague]

68. DANCE, LITTLE MAN, DANCE!

[Sognefjord]

64. This is essentially the argument used by C.S. Lewis to prove Christ's divinity.

Lewis said either Christ was nuts saying he was the Son of God or he was the Son of God in actuality. This argument was, I think, in Mere Christianity.

[Recursion]

66. D'oh. I read it wrong the first time. It's a perfectly valid syllogism

J -> G ^ M
J ~M
: J -> G

Formally valid, the major premise is just completely false.

(Valid syllogisms need not lead to true conclusions, remember.)

[Iterate]

67. Warm beer is better than nothing.

Nothing is better than God.
Therefore, warm beer is better than God.

I doubt anyone here wouldn't fail to parse it, but it might occupy a fundy teacher long enough to spare one child from abuse.

[Democracyinkind]

69. Proud of DU... I have a Master's in Philosophy (though not focused on symbolic logic)...

False Dichotomy is what I would have said, too.

[bemildred]

71. I wonder if that goober believes that himself or is just brainwashing the kids.

That is not symbolic logic. Symbolic logic looks nothing like English. That is a valid syllogism with a false premise, Aristotle would think it's very witty.

Also, logic proves nothing, logic is about valid reasoning, not valid results. You can prove the moon is made of green cheese, but that does not compel the moon. This is why empiricism has become such a big fad the last few centuries.