Read Critical thinking for Students Online
Authors: Roy van den Brink-Budgen
Critical thinking for Students (16 page)
It’s taken as straightforwardly the case that, if we have one claim supported by another, then the claims strengthen the case for their acceptance. Thus in a court of law, having more than one eye-witness giving the same account is seen as lending very useful weight to that version being accepted. This issue of the power of corroboration works wherever we find it.
Similarly, the lack of corroboration is seen as a potential source of weakness. This is especially so if it is not just that there is this lack, but where there is conflicting evidence. (‘The
Titanic
did break in half before she sank.’/‘The
Titanic
did not break in half before she sank.’)
You can begin to see that using credibility criteria is a bit like playing Top Trumps. A criterion such as expertise will often (perhaps even normally) trump one like vested interest. Someone with sufficient access who has a good reputation and who is neutral might go on to trump expertise. And so on …
You can therefore see how the credibility of claims can be seen as strong or weak, according to how the criteria stack up.
For example, what combination could give us very strong reasons to believe the evidence?
Relevant expertise + ability to perceive + neutrality + good reputation = more credible source
What combination could give us very strong reasons to doubt the evidence?
Lack of relevant expertise + lack of ability to perceive + bias (including vested interest) + poor reputation = less credible source
Let’s now look at an issue we first came across in Chapter 7 when we looked at appeals to expertise. This is the vexed issue of organic food.
The Food Standards Agency (FSA) commissioned a study of the health and nutritional value of organic as opposed to non-organic food. They asked the London School of Hygiene and Tropical Medicine to carry out this study. The leader of the team was Dr Alan Dangour, an expert in public health nutrition.
The team looked at 52,000 scientific papers which had been published between January 1958 and February 2008. Only 162 of these papers were seen as relevant, and only 55 of these were seen as of sufficient quality to be useful for the study.
They concluded in their report of 2009 that there was no significant benefit for health and nutrition from drinking milk, eating meat, vegetables, fruit and eggs from organic sources as opposed to non-organic ones.
The Soil Association says that it is a ‘charity campaigning for planet-friendly food and farming. We believe in the connection between soil, food, the health of people and the health of the planet’.
The review by the Food Standards Agency, it claims, looked only at papers written in English, and ignored recent research carried out by the European Union which was completed in April 2008. This involved 31 research and university institutes and the publication of over 100 scientific papers. This research showed that ‘levels of a range of nutritionally desirable compounds were shown to be higher in organic crops’ and that ‘levels of nutritionally undesirable compounds were shown to be lower in organic crops’.
So what do we do with these competing claims?
Let’s apply the credibility criteria to them and see what happens.
Let’s look for neutrality first – it’s always a very important criterion.
We perhaps need to know something about the Food Standards Agency. Is it neutral in all of this? (Or is it a front for the non-organic farmers’ lobby?) This is what they say about themselves:
The Food Standards Agency is an independent Government department set up by an Act of Parliament in 2000 to protect the public’s health and consumer interests in relation to food.
There was the crucial word – ‘independent’. If we take it that the FSA is as good as its word, then we’ve got a neutral organisation here. However, all the FSA did was to commission the report, not write it. (But one could say that an independent organisation is not going to commission a study from a biased organisation.)
What about the London School of Hygiene and Tropical Medicine? They describe themselves here:
The London School of Hygiene and Tropical Medicine is Britain’s national school of public health and a leading postgraduate institution worldwide for research and postgraduate education in global health.
There’s nothing there to suggest anything but neutrality. Nor is there with regard to Dr Dangour.
The Soil Association, however, is (by its own admission) not a neutral organisation. It is very much pro-organic and against non-organic farming. This doesn’t mean, of course, that its claims are not to be trusted. But it does mean that we would have to take its bias into account.
The European Union can be taken as neutral in this debate, being not obviously on one side or the other.
There’s a lot of expertise about, so let’s have a look at this criterion. Here’s the London School of Hygiene and Tropical Medicine again:
Part of the University of London, [it] is the largest institution of its kind in Europe with a remarkable depth and breadth of expertise encompassing many disciplines.
It’s self-claimed expertise but it’s unlikely that we’re going to disagree. In addition, Dr Dangour’s expertise is straightforwardly relevant. So what about the Soil Association? Their origins go back to 1946 and they have been concerned with developing organic standards since the 1970s. They clearly have expertise in this area, being able to provide expert advice to farmers and other groups.
With regard to reputation, we have nothing to worry about with any of these organisations. That of the London School is obviously considerable; the Soil Association provides the accepted standards for organic food.
So far, the criteria seem to have given a fairly evenly-matched contest (although the anti-organic case has so far scored a hit with regard to neutrality).
Let’s bring in ability to perceive/sufficient access to see whether this separates the two sides. You will remember that Dr Dangour’s team looked in all at 52,000 papers. This is an impressively large number. However, the Soil Association claims that Dr Dangour looked only at papers written in English, and did not take into account recent papers which showed the advantages of organic over non-organic food. This might limit the force of Dr Dangour’s sufficient access but, in turn, we don’t know whether the EU study took into account the papers studied by Dr Dangour and his team. So a bit of a cherry-picking draw there.
We’re now into the area of motive. Is there any bias and/or vested interest? We’ll have to acknowledge straight away that there is. The Soil Association’s lack of neutrality on this issue has to be seen in terms of vested interest. If organic food was shown to have no health or nutritional advantages, then they would cease to have a justification for continuing to be active in promoting such food
in these terms
. However, there’s no obvious vested interest on the other side (unless you can think of some!).
So it looks as if the Soil Association has lost on points …However, the Soil Association comes in with a late challenge. They point out that the FSA’s restriction of the terms of reference to just looking at food (understandably, of course) ignores the wider issues of the (possible) effects of pesticides on health. For example, they refer to EU research that showed links between pesticides and certain cancers, male infertility, and nervous system disorders. They also refer to claimed environmental advantages of organic farming (although there is disagreement on these). In addition, there are higher animal welfare standards with organic farming …
So looking at the credibility of evidence took us so far, and then we’re still left puzzling. Like custard, the claims started to run through our fingers even though we tried to hold them down. Who won this debate? You decide.
Having got this far, we have seen how Critical Thinking, with the right approach, equips us with the skills of being able to understand and evaluate the claims and inferences in arguments.
But it should also do something else. It should equip us with the skill of being able to produce arguments. This is because, in an important way, we are doing the same thing. In producing (presumably, what we take to be good) arguments, we are looking at the significance of claims in order to see how inferences can be drawn from them.
So let’s look at a list of things to do when putting together an argument.
•
Look carefully at the relationship between claims and inferences.
Ask
yourself
whether the claims (especially evidence-claims) are sufficient for the inference. What significance are you giving the claims? Could they have a different
significance
? Should the inference be reduced in scope to fit the claims better?
Alternatively
, do you need to add to the claims in order to increase the power of the reasons?
•
Be aware of the possible power of the counter-argument(s).
It can be a good idea to include this (them) and show how you can deal with such argument(s).
•
Look to draw inferences on the way to the main conclusion.
This can be useful in showing how your argument is built up, stage by stage. It’s also useful for you to check that the lines of inference are working as they should.
•
Consider the role of evidence both in providing and in supporting the
reasons
.
Evidence can help in both of these ways. But you need to ask stern
questions
of your evidence. Is it of sufficient value to be able to use it in this way?
Does it over-generalise? Are there
post hoc
issues with it? And so on. There’s also the point about counter-examples. What force do they have? Not much, if they are merely examples of the occasional exception. But an example of yours might well be able to be stopped in its tracks by a counter-example.
•
Don’t worry that your argument will be built on assumptions
.
As we have seen, most arguments are. Those who say that a good argument should not contain assumptions are not competent Critical Thinkers. But, having said that, do be careful that the assumptions aren’t necessary to bridge large shifts in the reasoning (as in slippery slope arguments).
•
Make sure that the argument fits together in a clear and coherent way.
The argument should proceed in steps that all contribute to the argument. An argument can gain strength by being well organised. This is partly as a result of the thinking you will have done in organising it: you’ll have thought about sequences of reasoning; you’ll have weighed up how the claims fit together; you’ll have used evidence in the appropriate places. But the strength also comes from how clearly the argument will read. It won’t distract the reader from the sequence of the case you’re arguing. You’ll take them by the hand and show them, bit by bit, what you want them to accept.
•
Make sure that the argument is consistent.
This is in some ways an aspect of coherence, but it’s also a reminder that the claims and inferences in the argument should go in the same direction.
•
If you use analogies, think carefully about whether the similarities outweigh the differences.
Analogies are a way of making a point with some force. But only if the analogy has sufficient similarities. Here’s one from Sir Martin Rees, President of the Royal Society (amongst other things). It’s in an article in which he’s arguing that everyone should have an understanding of science. ‘You can appreciate the essence of science without being a scientist in the same way that you can appreciate music without being able to read a score or play an instrument.’ What do you think? ‘In the same way’: is it?
•
Using hypothetical reasoning can give strength to an argument.
It allows you to explore lines of reasoning, without having to fully justify them. It allows you to fly kites to see how and where they might go. But do remember that hypothetical reasoning can support no more than hypothetical inferences.
•
Apply the standards that you would use to evaluate other arguments to your own.
Would you allow that evidence to be used like that? Would you allow that line of inference to go unquestioned? Would you stress that a different
conclusion
should have been drawn?
So that’s it. You can do all these things. You can analyse and evaluate the lines of inference that are out there, in all their varieties (from the oddities of certain newspapers’ online contributors to the arguments of the Astronomer Royal). You can also produce arguments which would meet the standards of the Critical Thinker.
So now you can reflect and comment on this item on the BBC website of 4 June 2009:
A sole can live cheerfully at a depth of 35,000 ft (10,933 m).
And this:
Americans are giving up their landlines at the rate of 700,000 per month. If this continues, the last cord will be cut in 2025. (
The Economist
, 13 August 2009)
Good thinking …