Skip to main content

Suggesting a new named fallacy: the Non Post Hoc Fallacy (or David Cameron Fallacy)

Many of us are familiar with the Post Hoc Ergo Propter Hoc Fallacy ('after this, therefore because of this) - Post Hoc Fallacy for short). It's the fallacy of supposing that, because B occurred after A, A must be the cause of B. For example:

My car stopped working after I changed the oil, so changing the oil caused it to stop working.


I wore my red jumper to the exam and I passed, so that jumper is lucky: it caused me to pass.

This fallacy is so common, it gets a latin name. However, there's a related common fallacy that I think also deserves a name. I am going to call it the Non Post Hoc Fallacy ('not after of this, therefore not because of this), or, perhaps more memorably, the David Cameron Fallacy.

Every now and then someone desperate to ‘prove’ that X is not causally responsible for Y – e.g poverty is not a cause of crime, will commit the following fallacy. They will argue that as X has often occurred without Y following, therefore X was not the cause of Y in this case.

Back in 2011 many right-wingers were desperate to show that poverty was not the, or even a, cause of the London riots. In order to try to show that, they pointed to poor people and areas where no rioting occurred. UK Prime Minister David Cameron said: “These riots were not about poverty. That insults the millions of people who, whatever the hardship, would never dream of making others suffer like this.” A letter to Newseek magazine argued: 'Saskia Sassen blames conditions in disadvantaged areas for the UK riots, ignoring urban areas for the UK riots, ignoring that other deprived regions – Glasgow, Tyneside, South Wales – didn’t riot.' That was fallacious reasoning. Compare:

Bert smoked 40 a day for 40 years and didn’t get lung cancer. Joe smoked 40 a day for 40 years and didn’t get lung cancer. Therefore Jim’s smoking 40 a day for 40 years did not cause his lung cancer.

Clearly, Jim’s smoking could easily be a – indeed the cause – of his lung cancer. True enough, smoking that much is not causally sufficient to produce lung cancer. Various other factors have to be in play too, including genetic factors, etc. However, the fact that only a minority of those who smoke 40 a day for 40 years end up with lung cancer does not show that smoking does not play a – perhaps even the – key role in producing the lung cancer of those who do smoke that much.

Journalist James Bloodworth made the same mistake back in 2016, arguing ‘The West is not responsible for Jihadist violence, Islamist ideology is.’ His argument? It’s as follows:

Yet if, as some suggest, American imperialism really is the “root cause” of modern anti-Western terrorism; if the West really has brought terrorism on itself, there are several questions that urgently require an answer. First of all, where are the Cuban, the Argentinian and the Chilean suicide bombers? Where are the Guatemalans and the Brazilians intent on the random slaughter of “unpure” populations and the mass capture of sexual slaves ? If fanatical religious ideology isn’t the main driver of the spate of recent attacks, where are the masked Latinos rampaging through parks and shopping centres with Kalashnikovs?

As any good anti-imperialist ought to know, outside of South East Asia there is arguably no part of the world that has suffered more under the heel of American imperialism than its own supposed back yard. The Middle East certainly hasn’t. Where, then, is the supposedly inevitable blow back . Source.

Now, as a matter of fact, I don’t doubt that Islamist ideology is a cause of Jihadist terror attacks on the West. But that doesn’t mean the West is not causally or morally to blame. The West may still be a, perhaps even the – root cause, as the smoking example illustrates. 

Notice that someone can, and plenty have, argued that Islamist ideology is not to blame for Jihadist terror attacks because the majority of those who sign up to Islamist ideology don't engage in terror attacks. That would be an equally crap argument analogous to Bloodworth's, but to the opposite conclusion - and another example of the Non Post Hoc Fallacy.

I think this fallacy deserves a name, and certainly needs to be more widely recognised given its popularity with dodgy politicians and journalists. It's right up there with slippery slope and ad hominem.


James Lenoël said…
Good piece, well argued.
Paul Braterman said…
Nice piece. One popular example: "I grew up in a slum, and look at me now. So you can't blame poor academic performance/poverty in adult life/crime/smoking and other drug use on slums".

Two closely related fallacies; single factor causation, which is itself a variety of binary thinking, and Who Is To Blame (one answer only, please)?
Anonymous said…
Hips are in, the curvaceous figure is back in style and wide hips are what it's all about, so read on, were going to give you some ideas on what kind of bikini looks best for women with wider hips.

A woman with a thicker torso has more options believe it or not when it comes to bikinis than a skinny torso, the reason for this is that fashion styles are changing and the movement in the fashion industry is a heavier, healthier look.

One of our favorites when it comes to bikinis for wide hips is the scoop front bikini. The scoop front style of bikini bottoms does two things, it elongates and smooth's the torso and the scoop front tends to give depth and further elongate the mid-section from the frontal view. For these two reasons, the scoop front bikini is by far our favorite recommendation when it comes to bikinis for wide hips. This scoop front bikini bottom will smooth and accentuate your curves and give your torso that perfect bikini look.

Popular posts from this blog


(Published in Faith and Philosophy 2011. Volume 28, Issue 2, April 2011. Stephen Law. Pages 129-151) EVIDENCE, MIRACLES AND THE EXISTENCE OF JESUS Stephen Law Abstract The vast majority of Biblical historians believe there is evidence sufficient to place Jesus’ existence beyond reasonable doubt. Many believe the New Testament documents alone suffice firmly to establish Jesus as an actual, historical figure. I question these views. In particular, I argue (i) that the three most popular criteria by which various non-miraculous New Testament claims made about Jesus are supposedly corroborated are not sufficient, either singly or jointly, to place his existence beyond reasonable doubt, and (ii) that a prima facie plausible principle concerning how evidence should be assessed – a principle I call the contamination principle – entails that, given the large proportion of uncorroborated miracle claims made about Jesus in the New Testament documents, we should, in the absence of indepen

Plantinga's Evolutionary Argument Against Naturalism refuted

Here's my central criticism of Plantinga's Evolutionary Argument Against Naturalism (EAAN). It's novel and was published in Analysis last year. Here's the gist. Plantinga argues that if naturalism and evolution are true, then semantic epiphenomenalism is very probably true - that's to say, the content of our beliefs does not causally impinge on our behaviour. And if semantic properties such as having such-and-such content or being true cannot causally impinge on behaviour, then they cannot be selected for by unguided evolution. Plantinga's argument requires, crucially, that there be no conceptual links between belief content and behaviour of a sort that it's actually very plausible to suppose exist (note that to suppose there are such conceptual links is not necessarily to suppose that content can be exhaustively captured in terms of behaviour or functional role, etc. in the way logical behaviourists or functionalists suppose). It turns o

Why do atheists think Christians believe unreasonably, if they don't?

How reasonable is it for the religious to believe the central tenets of their respective religions? According to many atheists: not very. Many atheists suppose it is in each case unreasonable for Christians, Jews, Muslims, Hindus, Bahá’ís, Quakers, Mormons, Scientologists, and so on to believe what they do. The religious person usually takes a different view of at least their own religious belief. They suppose science and reason do not significantly undermine, and may indeed support, the core tenets of their own faith. The same is true of non-religious theists. They consider their brand of theism is reasonably, or at least not unreasonably, held even if no particular religion is. Indeed, many theists consider atheism unreasonable. Even when participants in discussions between atheists on the one hand and defenders of some variety of religious or theistic belief on the other include intelligent, philosophically sophisticated and well-informed people striving to think carefully and objec