The Is-Ought Problem

June 27th, 2006

Posted by: Roger Pielke, Jr.

Al Gore obviously hasn’t read Andrew Dessler’s book:

. . . if you accept the truth of what the scientific community is saying, it gives you a moral imperative to start to rein in the 70 million tons of global warming pollution that human civilization is putting into the atmosphere every day.

This is a fine example of the is-ought problem described by philospoher David Hume. ASU’s Brad Allenby has explained why we should care about the is-ought problem in science:

. . . the elite that has been created by practice of the scientific method uses the concomitant power not just to express the results of particular research initiatives, but to create, support, and implement policy responses affecting many non-scientific communities and intellectual domains in myriad ways. In doing so, they are not exercising expertise in these non-scientific domains, but rather transforming their privilege in the scientific domains into authority in non-scientific domains.

11 Responses to “The Is-Ought Problem”

  1. Neil Says:

    Really, the is/ought problem is rather different than what is supposedly a fallacy promoted by Al Gore. The real is/ought fallacy is to presume that the way things are, in itself, shows us how they ought to be. For example, one looks around and sees people exploiting other people, notes this is “natural”, been going on for ages, and falsely thinks it is right to do. (That is, the real is a template for the ideal – rather than the classical position that the ideal is judgment for the real.) However, Gore is just using a commonplace moral good argument – that we shouldn’t let the earth get much warmer because of the disturbing effects that would have – and saying that, once we can be sure of the cause, we are morally obligated to oppose the cause. That is fully traditional ethical reasoning with no fallacy, whether you agree with either the certainty of global warming, or on just what trade offs are acceptable.

  2. 2
  3. Mark Hadfield Says:

    Al Gore is not a scientist and AFAIK claims no “privilege in scientific domains”. He is taking the *results* of scientific expertise on matters of fact and drawing conclusions, which he is then urging the rest of us to accept. This is a perfectly reasonable thing for a politician to do and better than the usual practice, which is just to make the facts up.

  4. 3
  5. David Jeffery Says:

    I don’t think that’s a fine example of the ‘is-ought problem’ or the problem that Brad Allenby discusses at all.

    The scientists’ ‘is’ is that we’re putting lots of greenhouse gases into the atmosphere and that will have impacts such as those Gore details in his film.

    To go from that to a scientist telling you ‘Therefore all emissions must stop’ would be an is-ought fallacy.

    But it’s not an is-ought fallacy for Mr Gore or for any other citizen to say “1. Assume scientists are right about the likely physical impacts of what we’re currently doing. 2. I can see for myself that those impacts are going to have negative (social, economic) effects on communities. 3. It’s reasonable to want to do something to avoid negative effects we can see coming. 4. Therefore, if the scientists are right, we should start doing something”.

    Saying exactly what we should do, based only on the science, would be an is-ought fallacy. That’s one for economists, the community, etc. Saying we should do *something*, based on the science and our knowledge that, say, increased droughts are something farmers aren’t going to like much, is no fallacy at all.

    What you’re saying is something like suggesting that a scientist studying pedestrian road deaths is making an is-ought fallacy when he looks both ways before crossing a road because his findings suggest failure to do so contributes to road deaths. He’d be committing the fallacy if he said we should put traffic lights or pedestrian bridges over every road. But to combine the science with easily observable common sense and say that it warrants some kind of response is no fallacy at all.

  6. 4
  7. David Roberts Says:

    It’s not a direct is-ought inference, Roger. There’s a second step implied, where a value statement is introduced.

    1. We’re running an enormous, uncontrolled experiment on our climate, with the very real possibility of changing it in ways that kill and impoverish large swaths of humanity.
    2. We don’t want to kill and impoverish large swaths of humanity.
    3. Ergo, we should stop pumping this crap up into the atmosphere.

    Perhaps he should have spelled out #2. Maybe he thought his audience would take it for granted.

  8. 5
  9. Roger Pielke, Jr. Says:

    David and David-

    Thanks for your comments. Both of you have exactly identified the problem here. With respect to both of your comments Al Gore skips over step #2.

    If this is to be a debate about morals, then at some point we have to be explicit about what the stakes are, and whether or not the various called-for actions can indeed achieve those goals. Assuming that values are widely shared is a big mistake.

    Both of you do just this — David J. called these values “common sense” and David R. suggests that Gore takes the values “for granted.” But this is exactly the problem. The values issues involved in the climate debate are complex and the issue is only common sense or obvious if one discounts the diversity of views on this subject.

    Gore’s approach encourages the waging of a debate about values through science. This is a common tactic of politicians and increasingly accepted by many scientists, but it is no way to resolve a debate about values that are in dispute.

    And the climate debate is nothing if not a debate about wha values we should prefer and the relative merit of conpeting means to achieve those disputed values. Until we recognize that fact and begin talking about them the debate will continue to miss the mark.

    See my discussion of Abortion Politics and Tornado Politics in this paper.

    Pielke, Jr., R.A., 2004. Forests, Tornadoes, and Abortion: Thinking about Science, Politics and Policy, Chapter 9 in J. Bowersox and K. Arabas (eds.) Forest Futures: Science, Policy and Politics for the Next Century (Rowman and Littlefield), pp. 143-152.


  10. 6
  11. Benny Peiser Says:


    I’m afraid Al Gore’s moral reasoning is extremely naïve and simplistic. Apart from the fact that there is no consensus on the future impact of climate change (in terms of costs and benefits), you only need to look at Europe’s faltering climate policy to realise that economic concerns have their own moral legitimacy. Indeed, they ultimately dictate any rational policy-making.

    Take Germany for example: The country is suffering from its worst economic slump since WW2. Germany has been the sick man of Europe for some time, with high unemployment, a stagnating economy and full-scale de-industrialisation in much of Eastern Germany.

    It is therefore commonsensical that the German government feel a moral obligation to safeguard its struggling economy from further harm to its competitiveness. No wonder, then, that Germany is increasingly reluctant to burden its struggling industries with additional Kyoto-related costs and higher energy prices.

    As the BBC’s Roger Harrabin reports:

    “The German government is about to trigger a new crisis in Europe’s flagship climate policy, the Emissions Trading Scheme (ETS). BBC News understands the German cabinet is likely to agree a deal that will reduce carbon emissions from industry by only 0.6% between 2004 and 2012. The decision is likely to influence other EU countries, including the UK, which still have to set their own caps. …

    The news will offer comfort to US climate sceptics who predicted that Europe would talk big on climate change but fail to impose large carbon cuts on its own industries. The decision represents a major success for the German business lobby….”

    Remember, this is the same country that has been Europe’s chief cheerleader for Kyoto and mandatory emission caps for many years. However, it is becoming evident now that German and European climate policies are gradually brought into line with those of the USA, Canada, Australia and much of the rest of the developed world. It would thus appear that Al Gore’s thinking on Kyoto has become rather outmoded.

  12. 7
  13. Rheticus Says:

    This is an aside, but I’m struck by the news piece referenced by the link to Al Gore’s name in the article.

    The news article opens with:
    “The nation’s top climate scientists are giving “An Inconvenient Truth,” Al Gore’s documentary on global warming, five stars for accuracy.”

    Yet as we get deeper into it more and more problems are revealed — in sharp contrast to one of the earlier quotes that could find no error in the movie.

    So the article presents with a ‘rally around and admit no error’ stance yet also can make the claim to be objective because it reports some errors in the movie.

  14. 8
  15. Mark Bahner Says:

    Roger Pielke Jr. writes, “If this is to be a debate about morals, then at some point we have to be explicit about what the stakes are, and whether or not the various called-for actions can indeed achieve those goals. Assuming that values are widely shared is a big mistake.”

    I think “values” are widely shared. However, I agree that there is profound disagreement over what the stakes are. David Roberts wrote:

    “1. We’re running an enormous, uncontrolled experiment on our climate, with the very real possibility of changing it in ways that kill and impoverish large swaths of humanity.”

    If I thought that was indeed a scientifically accurate statement, I’d be the *first* person in line, shouting that something needs to be done. (To give only one selfish reason, it would mean job security until retirement for a person with my background…an engineer, with specific experience and interest in energy systems.)

    But the simple fact is that I don’t think that David Roberts’ statement is even close to scientifically accurate. In fact, I would not put climate change in the top 5 of humanity’s *environmental* problems, let alone the top 5 of humanity’s overall problems (e.g., including such things as malaria, AIDS, potential for fanatics to acquire nuclear or biological weapons, etcetera).

    While I have not done (and have never seen done) a careful analysis of the number of lived lost versus saved by climate change to date, I would not be surprised if more lives had been saved than lost. I would not be even be surprised if that answer held true for another degree or two (Celsius) of temperature rise…which is all I expect in this century.

    I’ve seen “An Inconvenient Truth.” It contained significant and policy-relevant distortions of climate change science. If climate change scientists give it “5 stars for accuracy” they’d better be working from a 10-star system!

    Mark Bahner (environmental engineer)

  16. 9
  17. Mark Bahner Says:

    Hi Roger,

    I’m reading your interesting article on tornadoes and abortions.

    In the meantime…I goofed again, and forgot to sign in before commenting. (Or save my comments before transmitting.) Could you retrieve my previous comments from the spam bin?


  18. 10
  19. Dan Hughes Says:

    Can anyone here direct me to a document, or documents, in which are described in detail the processes and procedures that were used to determine that it is in the best interest of all the citizens of the United States that CO2 emissions be reduced. Additionally, documents in which the processes and procedures were actually applied to arrive at such a decision are of interest.

    Can you also direct me to document(s) in which cost-benefit studies for a CO2 policy, if such a policy exists, including optional cost-benefit studies for the same funds but used in other policy areas (trade-off studies) are reported? That is, in which determination that a CO2 policy is a better application of the costs than all other optional applications is demonstrated.

    This latter assumes that we have limited money to pay for all important applications in contrast to simply adding additional policies notwithstanding the costs.

    If it has not yet been determined that the best interest of all the citizens of the United States will be served by CO2 emissions reductions, why are scientists becoming social-policy advocates and insisting on making social policy?

    Thank you for your assistance.

  20. 11
  21. Benny Peiser Says:


    One recent document of relevance to your question is the Copenhagen Consensus 2006 – A United Nations Perspective (although it’s not limited to US policies)

    Of all the world’s pressing problems, costly actions on climate change rank last

    Interestingly, this commonsensical cost-benefit approach seems to be gaining currency among both the US and the UN

    It would even appear that Germany, as I mentioned earlier, is beginning to apply prudent cost-benefit analysis to their new climate policies, as this latest news report indicates:

    Germany, one of the big European countries that has taken the lead in trying to control climate change but that is also one of the biggest emitters of greenhouse gases, announced changes Wednesday that would allow increases in its emissions.

    The move, which weakens the European Union’s carbon trading program for the 2008 to 2012 period and could persuade some other countries to slacken their controls, could pit Germany against the European Commission….

    Climate change will also be one of the topics raised during the Group of 8 summit meeting of industrial countries next month in St. Petersburg.

    Germany, however, has tried to limit the discussion on climate change, while Britain is still fighting hard to put the issue high on an agenda that is expected to be dominated by energy security….

    It would appear that Angela Merkel is taking the lead in Europe on new climate policies. I woldn’t be surprised if Tony Blair would follow suit.