Don’t attack the straw men: Straw man fallacies and reductio ad absurdum fallacies

strawmanPeople love to argue. We all have views and opinions, and we tend to promote them prominently and viciously attack opposing ideas. There is nothing inherently wrong with that as long as your views are evidence-based and you use proper logic when attacking your opponent’s position; however, many people fail at this and succumb to logical fallacies. One of the most common blunders is something known as a straw man fallacy. This occurs anytime that you misrepresent your opponent’s argument, then attack that misrepresentation instead of the view that they actually hold. It is a fairly simple concept, but it is often misunderstood, and it is rampant in debates (this year’s presidential election has been full of a sickening number of these fallacies). Therefore, I want to talk a bit about this fallacy and when it does and does not occur, as well as explaining a particular subset of straw man fallacies known as reductio ad absurdum fallacies.


Straw man fallacies

Let’s begin with the basics, what are straw man fallacies? To put it simply, they are distortions of an argument that usually present a weak and easily defeated version of the actual argument. In other words, one debater will claim that their opponent believes view X (which is a distorted and weakened version of what their opponent actually believes), then they will explain why X is wrong. The problem with this should be obvious. If the opponent does not actually believe X, then showing that X is wrong does nothing to address the opponent’s actual beliefs. In other words, it doesn’t matter if X is wrong if X isn’t actually what your opponent is claiming. Nevertheless, this fallacy can be an extremely persuasive (albeit invalid) debate tactic that many people are duped by.

On that note, it is worth mentioning that although straw man fallacies can be deliberate, and many people use them with the intention of deceiving their audience, they can also occur unintentionally. This usually happens when someone is ignorant about the topic that they are debating, and I frequently encounter these arguments when talking to people who reject scientific results. For example, one of the most common creationist arguments is, “if we evolved from monkeys, then why are there still monkeys?” This is a straw man fallacy because evolution does not state that we evolved from monkeys (or even great apes). Rather, it states that we share a common ancestor with them. Thus, by making this argument, creationists are not in any way shape or form presenting a legitimate criticism of the theory of evolution, because they are attacking a claim that evolution does not actually make. Similarly, I often encounter religious people who say that climate change can’t be true because their religion says that the earth won’t be destroyed, and climate change says that it will be destroyed. If you actually understand climate change, however, then the problem with that line of reasoning is obvious. Namely, climate change does not claim that we are going to destroy the earth. Climate change is a serious problem, but it won’t cause our extinction.

I wanted to use those two examples not to attack creationists and climate change deniers, but rather to illustrate an important point: you need to understand a given topic before you decide whether or not to accept it. Otherwise, your arguments will often be straw men fallacies, and they will make your opponents think that you are ignorant, rather than making them actually consider your position. Further, this is important for far more than just winning debates. I personally care more about knowing what is true than I care about winning a debate, but if I have not even bothered to learn the fundamental concepts of the opposing position, then I can’t have any confidence in my conclusions. You need to actually study a topic thoroughly, before you reach a conclusion, and defiantly before you try to debate someone on it.

What isn’t a straw man fallacy

When it comes to the internet articles, public debates, and other venues where someone is not specifically debating you, do not assume that someone is committing a straw man fallacy just because they did not address a specific argument that you personally think works. In other words, if they attacked an argument that essentially no one actually uses, then they committed a straw man fallacy. However, if they attacked an argument that many people use, then they did not commit a fallacy even if you do not personally use that argument.

Let me give you an example of what I mean. Last week, I wrote a post debunking 25 common arguments against climate change (mostly arguments that climate change isn’t happening or we aren’t causing it). All 25 of them are arguments that I personally encounter frequently when debating people. Nevertheless, some people were quick to accuse me of committing a straw man fallacy, and they did so based on the grounds that they personally accept that we are causing climate change, but simply debate the amount of change that will happen (which is not a line of reasoning that I addressed). So, did I commit a straw man fallacy? No! Every argument that I addressed is an argument that many people actually use. The fact that some people have arguments that I did not address does not make the arguments that I did address fallacious. I cannot predict the argument that every single reader of my blog will use.

To be clear, if I had made grand, generalizing claims like, “everyone who debates climate changes believes these arguments” or “these are the only arguments against climate change,” then I would have committed a straw man fallacy. Similarly, if I was actually directly debating one of these people, and they said, “I accept that climate change is true, but I disagree about its extent” and I responded by providing them evidence that it was true, then I would have committed a straw man fallacy, because I would not actually be addressing the argument that they had made to me. I cannot, however, be held responsible for failing to predict every single argument that anyone anywhere in the world would ever make.

A similar example frequently occurs with anti-vaccers. I often write and share posts about vaccine effectiveness, and almost every time that I do, I get some angry anti-vaccer yelling at me with statements like, “This is such nonsense. The issue is about whether or not vaccines are safe, not whether or not they work!” As with the climate change arguments, however, there certainly are people who accept that vaccines work but erroneously think that the costs outweigh the benefits; however, there are also many people who do, in fact, deny that vaccines even work. So unless I am specifically addressing a group of people who are arguing about safety (rather than effectiveness), there is nothing fallacious about discussing vaccine effectiveness, because many people do actually argue that vaccines aren’t effective.


Reductio ad absurdum fallacies

At this point, I want to shift gears slightly and talk about another type of logical fallacy that is really just a special case of the straw man fallacy: reductio ad absurdum. That may sound like a Harry Potter spell, but it is actually a logical fallacy that occurs when you take a position, stretch it to an absurd conclusion that would not actually be supported by the original statement, then claim that the original statement must be wrong because the conclusion is clearly absurd. That may have sounded complicated, so let me give you a few examples.

On several occasions I have shared posts which explain that most people don’t need to take extra vitamins and dietary supplements because they already get a sufficient amount from their diet and their body can’t really utilize excess amounts. Whenever I share these posts, however, I almost invariably get responses like, “You’re such an idiot! You claim to be a scientist and you don’t even know that vitamins are important!? You would die without them!” Let’s think about this for a second. Did I claim that vitamins aren’t important or that your body doesn’t need them? No, I didn’t even imply it. There is a huge difference between saying that you don’t need to take excess vitamins and saying that you don’t need any vitamins. In other words, the argument that I presented states that most people in industrialized countries already get the vitamins that their bodies need from their diets, and they don’t need to take extras. Internet trolls then took that argument and stretched it to the absurd conclusion that vitamins weren’t necessary at all, then accused me of being an idiot based on that clearly absurd conclusion. Do you see the problem? The conclusion that they presented was based on a distortion of my argument, rather than the argument itself.

To give one more example, on several occasions I have shared posts that explain why juice cleanses and “super foods” can’t actually boost an already healthy immune system, and the wonderful people of the internet usually respond by asserting that it is obvious that a healthy diet is important and your immune system won’t function well if you’re malnourished. As with the vitamin argument, however, I never asserted that a healthy diet isn’t necessary. I was talking about boosting an immune system above its normal functioning levels, not basic nutrition. In other words, saying that you can’t boost a healthy immune system is not the same thing as saying that you can eat nothing but junk and expect to be healthy.


Reductio ad absurdum logic

This illustrates the correct use of reductio ad absurdum logic. The second stick figure is sarcastically illustrating that if the argument that science has been wrong in the past actually invalidated a current scientific result, then we could use that argument anytime that we wanted, but that would obviously lead to absurd conclusions. Note: sarcasm is not a requirement for reductio ad absurdum logic, but it is often included.

This illustrates the correct use of reductio ad absurdum logic. The second stick figure is sarcastically illustrating that if the argument that science has been wrong in the past actually invalidated a current scientific result, then we could use that argument anytime that we wanted, but that would obviously lead to absurd conclusions. Note: sarcasm is not a requirement for reductio ad absurdum logic, but it is often included.

Finally, it is important to note that reductio ad absurdum logic can actually be applied without committing a fallacy if you can show that the actual argument that your opponent is using would lead to an absurd conclusion if it was applied consistently. As long as you do not distort the original argument, then this technique is not only valid, but it is extremely powerful (it is one of my favourite tools).

Let me give you an example. I often encounter people who say things like, “all that I need to know about climate change is that Al Gore thinks it is happening. If he thinks that it is true, then it must be wrong!” This argument is technically a guilt by association fallacy, but we can easily demonstrate the flaw in it by using reductio ad absurdum logic. In this case, I usually counter this claim by pointing out that Al Gore also thinks that we are breathing oxygen, so if we use this argument consistently, then we must conclude that we are not in fact breathing oxygen. Do you see why that response works? I did not distort the argument, rather I showed that it actually would lead to an absurd conclusion if it was a good argument. I can prove this by setting up two identical syllogisms.

Original argument:

  1. If Al Gore thinks that something is true, then it must be wrong
  2. Al Gore thinks that climate change is true
  3. Therefore, climate change is wrong

Analogous argument using reductio ad absurdum logic:

  1. If Al Gore thinks that something is true, then it must be wrong
  2. Al Gore thinks that we are breathing oxygen
  3. Therefore, we aren’t breathing oxygen

See how this works? I simply took the original argument, applied it to a different topic, and showed that if we apply that argument consistently, we arrive at an absurd conclusion. I provided many more examples of this debate tactic in this post on consistent reasoning, so please see it if you are confused. You should also watch John Oliver, because he wields this logical tool brilliantly (sometimes he does also slip into reductio ad absurdum fallacies, but that is generally to set up a joke rather than make a serious argument).



In short, straw man fallacies are simply distortions and misrepresentations of your opponent’s argument. They can be intentional or unintentional, but they are easy to avoid by simply being well-informed on the topic that you are debating. Nevertheless, many people continue to use them and incorrectly accuse other people of using them. Additionally, these fallacies contain a special subset of fallacies known as reductio ad absurdum fallacies. These occur when an argument is stretched to an absurd conclusion that is not supported by the original argument. Although that strategy is fallacious when the argument is distorted in the process, it can also be a very powerful debate tool if you can demonstrate that the original argument itself actually leads to an absurd conclusion when it is applied consistently.

Note: I want to be clear that on topics like vaccines, climate change, evolution, etc. there really aren’t “two sides.” So I when I say that you need to thoroughly study the topic before reaching a conclusion, I am not suggesting that you need to read a bunch of conspiracy blogs, creationist websites, etc. Rather, you need to study the peer-reviewed literature (including the handful of studies that disagree with the consensus). You don’t need to read unreliable sources in order to be well-informed. However, if you want to actually debate people about these topics, then you really should spend time studying those unreliable sources, because if you don’t, you will often end up committing straw man fallacies. Indeed, I have seen my fellow skeptics do that on several occasions (and I’ve probably unknowingly done it myself at some point).  

Related posts

This entry was posted in Rules of Logic and tagged , , , . Bookmark the permalink.

11 Responses to Don’t attack the straw men: Straw man fallacies and reductio ad absurdum fallacies

  1. kishoreragi says:

    Dear blogger,

    It is more important to focus on the subject than promoting others views (climate research). If you are really good at the subject, please talk about it and convince why you are right. Telling only that CO2 traps energy won’t confirm your claim. You don’t even know how much a molecule of CO2 traps energy. As I said, your subject and technical knowledge is very poor in climate modeling. Furthermore, we don’t want your philosophy (fallacies) on the subject discussions.

    What do you know about the climate modeling issues? Do you know what kind of models CAN be used for the future projections because of the computer speed? Do you know what resolution is possible for the global models for predicting centuries ahead? Do you know what sub-grid scale processes are? Do you know the cost of error of the sub-grid scale processes in predicting climate? Have you ever seen how the processes are parameterized? Do you know why people out there use several models (ensemble) rather than single model for the confidence? Do you think that, if several people ( models here) do make mistake, it becomes right? These are some of the things that you have known before making claims. If you are confident enough for your claim, please talk about these in next post.



    • Fallacy Man says:

      First, you seem to be under the false impression that my blog is devoted entirely to climate change, which it isn’t. It is about science and logic in general (as you will notice in the title). Thus, this post was not about climate change. It was about logical fallacies, and it simply used some examples from climate change (as well as other topics).

      Second, understanding logic is absolutely essential for science and evaluating arguments. So when someone says something like, “Furthermore, we don’t want your philosophy (fallacies) on the subject discussions” I hear, “I know that I am right and am unwilling to change my view.”

      Third, since you are coming back to CO2 again (even though I never mentioned it in this post), I ask you again to explain the evidence that our CO2 is causing the earth to trap more heat. In our previous conversation I presented you with direct, empirical evidence that our CO2 was actually trapping more heat. I showed you direct measurements, not models, and you have continued to ignore that. Again, you keep harping on the predictive models, when I have repeatedly said that they aren’t what I am basing conclusions on. That, my friend, is why it is important to understand fallacies (i.e., you are committing a straw man fallacy).

      Finally, and most importantly, I ask you again for evidence. You keep insisting that the models are inadequate, scientists don’t know what they are doing, the entire scientific community is wrong but your superior knowledge has allowed you to see the truth, etc. Yet you have presented exactly zero evidence to support that.

      You and I went round and round ad nauseum on the previous thread, and you never presented any evidence to back up your claims, so I see no reason to continue this. Fare well.


      • kishoreragi says:

        I did not think that your blog is devoted only to climate change because I read before to know what you write about. I appeared again here because you indirectly mentioned me here in the post. I hope I accept it and I believe you don’t fall under “a straw man fallacy” !

        You, me and all others are same and have same ability, but molding the minds by themselves or by others make one different from others. The blogs like you have are misleading the science by saying the science is settled and climate is changing due to human-actions (of course you corrected later yourself by saying the human cause is dominating), so I present here. As far as I remember, I did not claim anything but refuted what you have been claiming. Therefore, you need to show solid evidence for your claim, not ME. What I have been saying from the beginning is that your evidence is not enough. Please accept it or show more evidence or ignore it. You did not do these three and you are still thinking that in your own way, I believe what you believe about climate change. I don’t know what kind of fallacy it is!

        Nearly, 100 years of climate research thought (still believing) that leaf boundary layer resists heat and moisture from plant leaves (not only climate scientist, but also plant physiologists). I refuted this and I have shown evidences with the help of beautiful guidance from my advisor. As a matter fact, boundary layers help flux (not resists) these fluxes because turbulent nature of the boundary layers. What leaf does is something different, but I am not going to go further into it, as it is not yet published. However, I will surely get back to you once it is online. It is critical issue because it supplies heat and moisture into atmosphere (please consider a large area tropical forests here so that you can understand the need of plant leaf regulation). Furthermore, I am getting into cloud microphysics (I hope you know it the most uncertain in the present climate models). I know the state-of-the-art cloud processes, but you need evidence. Please see IPCC report ” Clouds and Aerosols; Boucher et al, 2013, Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change”). Please wait for a couple of years, so I update where the problems are in the present cloud processes and how we have corrected some of those processes and how to go about it. I would like to give clue here. Clouds and chemistry are fully interactive, but the present state of the models do not consider much. One caution here (because I found you jump at something suddenly). You read few articles and say that the science is showing that there is aerosol-cloud interaction. That is not what is exactly done.

        Finally, I can’t show the evidence for your claim because I need to do a lot of corrections through my research before claiming something big like this.



        • Fallacy Man says:

          I want to make a few brief clarifications.

          First, I actually wasn’t referring to you at all in this post, as you never accused me of a straw man fallacy.

          Second, I never said that we were the only factor at play. You incorrectly inferred something that I did not state or imply.

          Third, and this is the important one, you seem to be misunderstanding what I mean by asking you for your evidence. I provided you will multiple papers, and you essentially just said, “nope they are wrong.” I have been asking you for evidence to back up that claim. In other words, I have been asking for evidence that those papers are wrong. You don’t get to ask for more evidence until you have discredited the evidence that has already been presented, and simply saying that you don’t accept those papers isn’t satisfactory.

          Nevertheless, as I said, we have been going round and round for a while and I simply don’t have time to continue. So I bid your fare well and wish you good luck on your research.


    • kishoreragi says:

      Thank you all for your decision down rating my comment. If you up-rate I can have clue that you agree with my idea, but here there is no clue why you refuted with me. People who are experts usually try to refute my comments by showing my ignorance.

      Please come out and discuss what I have posed here or I may have to leave this place as it is not my place, and I have to choose a better place.

      Thanks and regards,


  2. Sceptom says:

    I’m not sure the Al Gore example totally works… I mean, it does if you don’t care to “read between the lines”. What I mean is that it’s difficult to express one’s view in one sentence. When someone says “all that I need to know about climate change is that Al Gore thinks it is happening. If he thinks that it is true, then it must be wrong!”, it might be the case that he’s indeed using the absurd reasoning you’re criticizing. But there might be other explanations. They might first mean only in the context of climate change and not any other topic. They might also have found super strong evidence that Al Gore was profoundly incompetent on this particular topic and decided not to trust what he says on the matter (that would still be invalid reasoning, for he might be right despite his incompetence, but it would be justified nonetheless to not trust him), or that he’s a pathological liar.
    it’s still wrong but it’s less absurd and your argument seems less convincing that way.


    • Fallacy Man says:

      I think that you might be missing the point. For example, you said, “They might first mean only in the context of climate change and not any other topic,” but my point is precisely that it is invalid to apply this reasoning only to climate change and nothing else. Similarly, when I have encountered this argument, it has always been made by someone who is politically conservative and is actually asserting that anything that Al Gore believes must be false.


      • Sceptom says:

        If someone is implying that everything Al Gore believe is false, that’s just plain absurd. I agree. If your example only meant to target this particular case, then I think it’s fine, perhaps a bit trivial even.

        But one could imagine, as I did, that other cases might apply, such as cases where only the topic of climate change is concerned. That’s not explicitly ruled out by your example because there’s always at least some degree of interpretation to be done on such a short statement. In such a case, and if you actually have ample evidence that Al Gore is completely incompetent on the matter (you don’t to assume anything about his competence in other matters), then the statement would be somewhat reasonable. Strictly speaking, still invalid, but reasonable nonetheless, just as you have argued in another post on the ad hominem fallacy (which is not really ad hominem if you can prove that someone is truly incompetent or a pathological liar). Of course, you would then need to actually demonstrate that you have such evidence.


        • Fallacy Man says:

          What your describing is very different from the context in which I have always heard this claim. I certainly have also heard people make an argument that is more inline with what you are saying, where they say something to the effect of, “Everything Al Gore said in ‘Inconvenient Truth’ was wrong, therefore climate change itself is wrong.” However, I also frequently hear people who are extremely politically conservative make blanket statements that Al Gore is so wrong/untrustworthy in general that if he thinks it is happening, then it must not actually be happening, and that is not a statement/view that can be restricted to climate change. If that reasoning worked, then it would be applicable to all of his views.


Comments are closed.