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May 25, 2006

Madsen Pirie tells you how to win every argument (and how not to fall for other people's arguments): How To Win Every Argument - Madsen Pirie

Posted by Tim Worstall

How To Win Every Argument: The use and abuse of logic
by Madsen Pirie
Pp. 192. London: Continuum, 2006
Hardback, £12.99

To anyone who plays with words for a living this is a profoundly depressing book. To find that for decades I have been committing most sins in the logical lexicon is dispiriting at the very least.

The book takes the form of an alphabetical list of the major logical fallacies, from abusive analogy (a version of the ad hominem) to wishful thinking (a particular favourite at The Guardian: because we'd like to raise the wages of the low paid a minimum wage will work, right?) via concealed quantification (imprecision about attributes of a class or simply members of it) and the well known straw man (oh, come on, we all know that one surely?).

Each entry has a short, a page or two, description of what is exactly the logical error, some examples of its use and more importantly for the budding debater, a few words of wisdom on how to employ it oneself, the whole suffused with Pirie's rather donnish wit. For example, the analogical fantasy consists of supposing that things which are similar in one respect must be similar in others:

The body politic, like any other body, works best when there is a clear brain directing it. This is why authoritarian governments are more efficient.

[None of these false analogies likening the state to a human body ever seem to say much about its liver, pancreas or waste disposal mechanism.]

Having had such error pointed out to us we can carry on detailing the errors: the human body most certainly does not have a conscious brain directing it in all of its actions, all of the really important ones such as heartbeat, kidney function and so on are under self-regulating control, intervention is only necessary when they go awry...and authoritarian governments are like the waste disposal system in the quality of their product.

A very useful analogy to employ, we are told, is that of the family: it gives everyone a nice warm feeling and justifies giving out the pocket money and sending the naughty ones to bed.

Bifurcation, or the black and white fallacy (giving only two options when there are in fact more) gives us this on Nelson's famous cry:

Westminster Abbey or victory!

[Overlooking the possibility that he might get both, or the option of St Paulís where he ended up.]

Cum hoc ergo propter hoc is what might more generally be known as the correlation/ causality problem. Simply observing that events coincide does not mean that one causes the other and it may even be true that our supposition is entirely backwards. Do elections cause higher spending? Certainly we can observe that people spend more in an election year but perhaps this is because governments facing election keep taxes down, leaving more to fructify with the population? The Independent is published each day and silliness exists in the world: perhaps the former is merely taking advantage of the latter rather than causing it?

A particular favourite of mine is the ex-post-facto statistic, so often used to deny evolution and insist upon a creator. The odds of the universe developing at all, and in a manner to allow us to thrive, are obviously so small that a designer must be inferred. Indeed, when you look through the numbers it does seem that way. However, we are here (absent the opinions of some schools of philosophy) so the ex-post-facto probability of our existence is in fact one. It may at the beginning have been unlikely, but the universe had to turn out some way so we cannot now look back and claim that it was directed to produce us.

We are all of us of course guilty of the genetic fallacy: that the merit of an idea depends upon where it comes from. We've seen it all over the newspapers recently, with the arguments that Hitler was against both fox hunting and smoking. Entirely true, but each needs to be argued on its own merits, not the connection with a Fascist dictator. Sadly, there is not, and never has been, anyone entirely wrong all the time, so we cannot reject an idea solely upon its provenance. No, not even those put forward by Ms Toynbee (difficult case I know, but not all the time).

I've been using the slippery slope fallacy myself a great deal recently: in fact I use it a great deal all of the time. I am chided for doing so here but am allowed a get out, in that sometimes it isn't in fact a fallacy. That first step off the roof of the skyscraper is indeed (almost, there was one recorded case of a lady going off The Empire State who got blown back in the window a couple of floors down,) inevitably going to lead to disappointment but in order for it not to be fallacious there cannot be choice about the subsequent steps.

One disturbing feature of reading through this was that after digesting a few more errors each evening (this is not something to drink at a draught, better to sip at it and digest) I would see them employed all over the newspapers the next day. Sometimes in genuine error but more often as disingenuous (or is that genuous?) rhetorical devices. This to me is the value of the book, having a handy guide to how people attempt to pull the wool over my eyes. Pirie suggests that it may actually have greater value as a guide to the employment of these tricks but of course as I don't write for any of the left wing outlets I am forbidden the use of such wiles.*

Tim Worstall graduated from the LSE and immediately went into small business where he has remained for twenty odd years, working in the US, UK and Russia in fields as diverse as newspaper distribution, offshore programming and exotic metals. He is the author of 2005 Blogged: Dispatches from the Blogosphere and blogs at

*A tricky use of a subset of the special pleading fallacy combined with an ad hominem, possibly dicto simpliciter, division, ad populum and even plain flat out lying.

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