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Dr David Grimes: challenge claims and stand up for science


Dr David Robert Grimes is this year’s winner of the John Maddox Prize for standing up for science. In this guest post, he argues that it’s important for us all to challenge extraordinary claims.

We often take for granted just how incredible the era we live in is. We’re the first generation in human history for whom information on any and all subjects is available quite literally at our very fingertips. This is incredibly empowering, but can sometimes be a double-edged sword…

While instantaneous access to practically the entire wealth of human knowledge is something that is now part of our lives, it is somewhat paradoxical that this same freedom of information allows falsehoods and misinformation to perpetuate further and faster than ever before.

Obviously then, sources matter when we must ascertain the veracity of any information. But evaluating sources can be a difficult task, and often impractical for an individual. Objective, well-sourced information is crucial if we are to make informed and pragmatic decisions. And evidence should be paramount in everything we do, from selecting a political candidate to support to choosing the best car to buy.

‘Extraordinary claims require extraordinary evidence’

From practically every aspect of the modern world, we are accosted by a multitude of claims, promises and warnings. But it is vital to remember that without evidence, any claim is merely sound and fury. Unless supporting evidence is offered, healthy scepticism should be our default position to any claim.

Carl Sagan’s dictum that ‘Extraordinary claims require extraordinary evidence’ is an excellent guiding principle in not only the scientific world, but in our everyday life too.

Continue to insist on evidence

However, while the onus for substantiating a claim almost always lies with the party asserting it, it is not uncommon for those making questionable assertions to claim it is the responsibility of others to prove them wrong, rather than for them to verify their statements. This is a rather devious tactic and it pays to be wary of this rhetorical fallacy.

It is important we don’t accept such attempts to wrangle out of providing evidence, and continue to insist on it. Asking for evidence is therefore important as it reminds those promoting their wares that the onus is on them to support their assertions.

From a consumer point of view, objective and verifiable information is of vital importance in making good decisions, and this is certainly something that the Which? Convo community has much to contribute to.

Do you challenge products that make extraordinary claims, such as the ‘drinkable sunscreen’ that Which? uncovered? What was the outcome?

This is a guest post Dr David Robert Grimes, a scientist at the University of Oxford. He was awarded the 2014 John Maddox Prize for promoting science and evidence on controversial issues, such as nuclear power and climate change. The award is named after the late Sir John Maddox, who was editor of Nature for 22 years. All views are David’s own, not necessarily those of Which?.


Whilst the assertion that only now have we unprecedented access to information of dubious veracity is true, it is a bit marginal. We have always been given information through newspapers, many of which have political support or agendas, correspondents of dubious expertise, prejudiced and partisan. So we have always had to use our judgement – if we could be bothered – to try and assess the truth. But unless you have all the evidence and good analytical skills that is very difficult. Which is why we have to rely on impartial experts and expert bodies to do this for us. And can we trust them? Climate change is perhaps a good example – conflicting views from so-called experts, and worse, from ignorant politicians.

I agree that evidence should vbe provided to support a claim – but this can be “economical” in supporting the claim.

What’s the answer? Probably only experience and education to help you make a best judgment.


My view is that all claims made in advertising should be scrutinised before products are put on sale. In the absence of evidence to support a claim, the advertisement should be rejected. The same would have to apply to claims made in other ways, e.g. packaging, product information and articles written by a company to promote sales. That’s a tall order and my view is that we are going to have to move towards companies paying for this scrutiny. This is not something that will happen overnight.

It is good to see the ‘Ask for Evidence’ campaign, promoted by Sense About Science: http://www.senseaboutscience.org Hopefully the new Ask for Evidence website (David has provide a link in his introduction) will engage with more people.

Even schoolchildren can be aware of marketing hype but how many of us are in a position to question whether claims used in current advertising are honest?


You raise a good point there – individually, it is very difficult to ascertain whether a claim is honest or not. Collectively, however, this becomes exponentially easier. One of the reasons I have so much time for Sense About Science is that they essentially serve as a central hub for this very purpose, and one that will improve as more people contribute to it. I’d love to see the system you mention implemented, but as you correctly point out it will certainly not happen overnight!


As in other “policing” areas this is a question of scale – imagine the number of adverts and then the number of experts, bodies and beaurocracy needed to adjudicate. I do not think it feasible.

I would rely on people in general and expert organisations reporting blatant advertising misrepresentation and requiring supporting evidence form the advertiser to support their claim. The cost of investigation should be paid by the advertiser, refunded only if the claims were true. If untrue, the company should be fined and, if fraudulent, criminal proceedings take. Is Trading Standards the starting point – if only we had a well-funded national organisation.

We do have to learn how to deal with persuasive adverts that are not untrue but appeal to our emotions. Every organisation that sells products or services wants to persuade you to buy, so will miss out the negatives. Is that misrepresentation?

How would MPs survive in this scenario?


Ask for the Evidence I am proud to say I used a few days ago querying the lifetime use claims on electrical drills.

However the problem remains that unless there are penalties for making unverified or unverifiable claims we are not much further forward in preventing them. The interesting case of Cokes Vitaminwater where its US counsel argued that a normal person would not believe that it contained vitamins is on record and googleable.


What’s the relevance of that piece? Cancer diagnosis has been rising for decades and will continue to rise as the population ages. You have to die of something, and the more you don’t die of injury, infection or heart disease, the more you’re likely to die of cancer.


Drinkable sunscreen I recall was vigorously challenged on Which? Convo as too absurd and real evidence of its efficacy was never substantiated. Claims such as these need science to protect the inexperienced young and the more vulnerable from exploitation. On the other hand, one cannot help but question where science is taking us. It has taken us to the moon and back and we have just landed a sophisticated piece of tackle on a comet 300m miles from our planet at great expense to determine our watery origins and yet one in three people are still dying of cancer.

One problem our scientific friends have never been able to explain to me is fundamental. I remember reading somewhere that to a scientist “if it can’t be measured then it doesn’t exist.” Paradoxically to produce something from nothing is the very essence of a scientific mind anyway.

Sorry for delving a little too deep but in my lifetime there are soooooo many things that have happened at a personal level that can be explained but not measured and I have yet to be convinced they did not exist.


Homeopathy has no supporting evidence so, on this basis, should be banned. However the NHS has some Homeopathic hospitals and some GPs practise it. Presumably these are scientifically-trained logical people. Just to illustrate the difficulty.

Is it just is important to disprove something as it is to prove it? On the one hand homeopathy may work, or the thought it will work might be sufficient to help some people; against