Saturday, 10 August 2013

A short course in logic

As a service to my delightful and discerning readership (one of whom recently commented that he read one of my posts with all due contempt, which I have to say is precisely the correct amount of contempt with which to read my outpourings) I have decided to offer a short course in logic.

It seems to me that not all are as well-acquainted with the formal processes of logical thinking as one might wish.

We will start with the syllogism, which is a valuable tool in analysing the formal validity or otherwise of an argument.

The syllogism is a three part structure.  Consider this proposition: a tomato is a fruit: therefore it is appropriate to put it in a fruit salad.

The fallacy here can be easily analysed by employing the structure of the syllogism to tease out the implicit missing middle step.

A: the first premise: A tomato is a fruit

B: the second premise: A fruit salad is made of fruit

C: the conclusion: Therefore it is appropriate to put tomatoes in a fruit salad.

Whilst both A and B are true, it is clear that C does not follow from A and B, and therefore the conclusion is (logically) false.  A closer analysis reveals that the faulty thinking lies in a misunderstanding at step B. To reach C, B would have to be: ‘It is appropriate to put any fruit in a fruit salad.’ 

So pay attention to the formal structure of the argument as implied by the way it is presented: that is, are the premises true? And does the conclusion follow from those premises?

To analyse that, you may need to extrapolate the implicit premises, and will certainly need to be quite clear about the meaning of all terms (words and phrases) employed.

Using that analytical approach, I invite you to find the flaws in the following (entirely hypothetical, you understand) illogical thought processes.

Lest anyone think that this post is aimed solely at him, I can assure such a delusional person that it is not. The examples have been drawn from a number of experiences over several years, and include thoughts I have caught myself developing and having to interrogate.  

However, if your collar is feeling unexpectedly hot, you may want to consider if you have, in fact, committed any of these howlers. Even if you have, it would of course be a logical fallacy to conclude either that you are the only person reading this to have done so, or that this post is all about you. 

(That example is drawn from something similar to something I have said. Therefore Ben is lying and this whole post is about me. And what’s more, I never even said many of these things, which proves Ben is lying, again! - Discuss.)

If anyone persists in thinking that this post is particularly about him, I refer him here.

(Ben has a rubbish taste in music. Therefore Ben is an idiot. Discuss...)

By the same token, I have used the name Ben throughout, though most of these howlers have been committed vis-a-vis others, and some of them by me.  So why have I done that? Because it amuses me to do so. (Ben has a rubbish sense of humour. Therefore Ben is an idiot. Discuss...)


There are sock puppets on Twitter who appear on your timeline and disagree with you. Ben has appeared in my timeline and disagreed with me. Therefore Ben is a sock puppet.

That alleged sock puppet was proved not to be a sock puppet.  Therefore all this talk of sock puppets is deluded.

Someone Ben follows has said something outrageous on Twitter.  Ben has remained silent. Therefore Ben approves.

Ben blogs and tweets pseudonymously. Therefore Ben is a coward.

Ben treats the accusations against him lightly. Therefore Ben treats the bullying of others lightly.

Online bullying is very damaging. Therefore everyone should agree with my approach to dealing with it.

Ben has done X in the past. Therefore Ben is clearly guilty of all Xs in the future.

Ben spends time on twitter and blogging. Therefore Ben is neglecting his wife and children

St Thomas More said: 'The Devil, that proud spirit, cannot endure to be mocked.’ Therefore when Ben gets upset at being teased, it proves he is under demonic influence.

Ben supports the Church’s teaching on {X}. Therefore Ben is a bigot.


Ben likes and promotes the EF Mass. He must be a nutter like those Rorate types.

Ben has criticised Catholic Voices. He must be an evil extremist.

Praying online is vain grandstanding. Twitterangelus is just showing off.

Ben has reason to believe that {X} is true. Therefore {X} is true.

Ben has blogged or tweeted something horrid about something I have said. Therefore Ben hates me.

Ben claims to be a Catholic, but is not perfect.  Ben is a hypocrite.

Ben has been the victim of bullying. Therefore to refer to anything he may have ever done wrong is victim-blaming.

Ben is on my side. Therefore he has done no wrong.

Ben’s {friend/enemy} is my {enemy/friend}

Ben’s failure to condemn bad behaviour in his friends, publicly, is to collude with it.

Ben has the right to ask AnyBen Else to justify anything. AnyBen who fails to comply is guilty or has something to hide (except for me and my monkey)*.

Ben has argued {X}. So has someone else. Therefore it’s a conspiracy.

Ben was talking to some pro-choice friends who were picketing a pro-life vigil.  Therefore Ben was betraying the pro-life cause.


Calling on your gang to join in your fight is a bullying tactic. Except when Ben does it.

Picking fights online is bullying. Except when Ben does it.

When you get something wrong, it is good to apologise and retract. Except for Ben.

Ben has expressed himself in intemperate terms. That proves it.

All who ask for RTs are indulging in vanity.

Ben has not seen X happen. Therefore Ben is to be castigated for not knowing about it.

Ben has behaved outrageously and wickedly on Twitter. Therefore it is {OK/my moral duty} to behave extremely badly towards him.


It should also be noted that (almost) any of these conclusions may be correct; my point is that, logically, they should not be arrived at by the arguments illustrated. 

Part of the problem is, of course, that Twitter limits one to 140 characters. But that is only part of the problem...  


*Lest anyone go apoplectic about this, it’s a reference to a popular band of my youth**. #WhoaretheBeatles?...


It has been kindly pointed out by my friend, the Part Time Pilgrim (@PartTimePilgrim), that where I wrote 'youth', I should have written 'infancy'. I apologise for the error and am happy to correct it. 


FrereRabit said...


Dilly said...

I hesitate to recommend this on Twitter, (though it is the most intelligent and self-effacing piece I have read in a while)in case it cements your reputation. I simply refuse to interact with the paranoid ones - you only ever stoke the flames of the paranoia. Am loathe to stand back and see them inflict their mentality on others though. Sins of Commission v Sins of Omission?

Bruvver Eccles said...

Ben has recommended fruit salad made with tomatoes. Therefore Ben is not to be trusted.

Tony Flavin said...

Any real people like this? So far the three comments could all be from the same person.

But one men's lesson in logic is another man's grizzle fest .

Tony Flavin said...

Tut, do I have to say it again.

There is no reason to believe the three comments above are not from one person.

One man's lesson in logic is another man's grizzle fest

Ben Trovato said...

I have strong reason to believe the preceding two comments are both from the same person. But I draw no conclusions from that hypothesis...

FrereRabit said...

If anyone is in any doubt about my identity, as clearly revealed, the last possible doubter should be Deacon Flavin, as I gave him - in all charity - a link to one of the best known priests in Southwark, to suggest a resolution to these problems. (A priest I have known for thirty years.) The idea that everyone is the Rabit - even now - is rather dull.

Wynn said...

Very good indeed. And particularly apposite to recent behaviour by the sad, the silly or the self-absorbed. As this thread itself exemplifies all too well.

A asserts x. B said something which might be held to be supportive of A's assertion. So did C. Therefore I may hypothesise that A, B, and C are the same person. If A, B and C are unable to, or decline to, produce conclusive evidence to the contrary, I may treat that hypothesis as proven. I may further conclude (1) that not-x is thereby demonstrated, and (2) that if A, B or C subsequently assert y, it may be taken as axiomatic that not-y.

How many logical fallacies can we count in that argument, children?

Tony Flavin said...

Earlier I said three contributors could all be the same person. Well of course, it could be all four posters, as has been pointed out to me.

Why a moderator would choose to post a double post other than to have a little dig I don't know . But you get to have a dig at the real person. I have the grave not to drag you out from your hiding place.

The priest that was alluded to was not able to assist us. Bit of a cheap shot to bother an elderly gentleman like that .

FrereRabit said...

This remark is an insult to the priest concerned, who in fact was genuinely suggested to Deacon Flavin by me as a spiritual help. In fact Flavin used the charitable offer in order to stalk me by pumping the priest for information about me. The continuing threatening emails from Flavin have precisely been the provocation for renewing the @missypigator character's presence. If it is the only way to keep him off people, it will continue.

(You may not publish this, but if you don't you will at least know what is going on.)

Gareth Thomas said...

Stepping out of sockpuppet mode and laying @Missypigator to rest in the sock drawer, I would say that if some people were genuinely offended, I am genuinely sorry. On the other hand, this tactic only came into use because a number of people been hurt over an extended period and few protested on their behalf as strongly. A knockabout pig-wife character and a cartoon deacon in a shed is hardly the same offence as the stuff that has been dished out over a long period designed to cause real pain. I will desist. I wonder if the other parties can learn something? I am still getting threatening emails, which is what began my involvement.

Tony Flavin said...

I have all the threatening Emails if anyone wants to see them. Just like another email from another occasion last year when my email was called threatening by the recipient but not by those who took up my offer to see it.

Funny that

Fake accounts are never acceptable, I've managed not to use one, to use one is cowardice.

A recent parody account has taken the opportunity to say something a real account was repeating last yesr. Just saying.

Bruvver Eccles said...

I wonder who was responsible for the fake account @bruvereccles, which is still there?

Ben Trovato said...

I tend to moderate with a light touch, but will always delete ad hominem attacks; so do not keep posting them.

I will also not publish any unsubstantiated allegations or speculations about the authorship of sock puppet accounts; or anything else which in my view tends towards either detraction or calumny.

JabbaPapa said...

whoops-a-syllogism !!!

Pétrus said...

I don't know who this Ben chap is but he sounds pretty ghastly.

Pétrus said...

From Tony Flavin :

"A recent parody account has taken the opportunity to say something a real account was repeating last yesr. Just saying."

Surely the most likely answer to that is person A read what was said by person B rather than Person A and Person B are one and the same?

retrochbabe said...

Logic is for cowards who never seek to find why society fits them with stuff collars ,for beurocratic who never seek to build taller towers .Logic is for crowd followers who never seek their own thoughts but parrot others .Logic is for those afraid to fly ,

Bruvver Eccles said...

Once you reject logic you are on the road to rejecting truth.

Bruvver Eccles said...

Or as Chesterton put it:

"...But, as a matter of fact, another part of my trade, too, made me sure you weren’t a priest.”
“What?” asked the thief, almost gaping.
“You attacked reason,” said Father Brown. “It’s bad theology.”