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Rationally Speaking is a blog maintained by Prof. Massimo Pigliucci, a philosopher at the City University of New York. The blog reflects the Enlightenment figure Marquis de Condorcet's idea of what a public intellectual (yes, we know, that's such a bad word) ought to be: someone who devotes himself to "the tracking down of prejudices in the hiding places where priests, the schools, the government, and all long-established institutions had gathered and protected them." You're welcome. Please notice that the contents of this blog can be reprinted under the standard Creative Commons license.

Wednesday, April 06, 2011

The Perils of Metaphorical Thinking

by Julia Galef
For an organ that evolved for practical tasks like avoiding predators, finding food, and navigating social hierarchies, the human brain has turned out to be surprisingly good at abstract reasoning. Who among our Pleistocene ancestors could have dreamed that we would one day be using our brains not to get an apple to fall from a tree, but to figure out what makes the apple fall?
In part, that’s thanks to our capacity for metaphorical thinking. We instinctively graft abstract concepts like “time,” “theories,” and “humor” onto more concrete concepts that are easier to visualize. For example, we talk about time as if it were a physical space we’re traveling through (“We’re approaching the end of the year”), a moving entity (“Time flies”) or as a quantity of some physical good (“We’re running out of time”). Theories get visualized as structures — we talk about building a case, about supporting evidence, and about the foundations of a theory. And one of my favorite metaphors is the one that conceives of humor in terms of physical violence. A funny person “kills” us or “slays” us, witty humor is “sharp,” and what’s the name for the last line of a joke? The “punch” line.

Interestingly, a lot of recent research suggests that these metaphors operate below the level of conscious thought. In one study, participants who were asked to recall a past event leaned slightly backwards, while participants who were asked to anticipate a future event leaned slightly forwards. Other studies have shown that our metaphorical use of temperature to describe people’s demeanors (as in, “He greeted me warmly,” or “He gave me the cold shoulder”) is so deep-seated, we actually conflate the two. When people are asked to recall a time when they were rejected by their peers, and then asked to estimate the temperature of the room they’re sitting in, their average estimate is several degrees colder than that of people who were asked to recall being welcomed by their peers. And in one study that asked participants to read the dossier of an imaginary job applicant and then rate his or her personality, participants who had just been holding a hot object rated the imaginary applicant as being friendlier, compared to participants who had just been holding a cold object.
Another classic example is the “morality is cleanliness” metaphor. We talk about people having a clean record or a tarnished one, about dirty dealings and coming clean. And of course, religions are infused with this metaphor — think of baptism, the washing away of sin. One clever study published in Science in 2006 showed how deep-seated this metaphor is by dividing participants into two groups: those in the first group were asked to reflect on something virtuous they’d done in the past, and those in the second group were asked to reflect on a past moral transgression. Afterwards, each participant was offered a token gift of either a pencil or a package of antiseptic wipes. The result? Those who had been dwelling on their past wrongdoing were twice as likely to ask for the antiseptic wipes.

Associating the future with the forward direction and the past with the backwards direction seems pretty harmless. But cases like “morality equals cleanliness” start to suggest how dangerous metaphorical thinking can be. If people conflate dirtiness with immorality, then the feeling of “Ugh, that’s disgusting” becomes synonymous with the judgment, “That’s immoral.” Which is likely a reason why so many people insist that homosexuality is wrong, even though they can’t come up with any explanation of why it’s harmful — any non-contrived explanation, at least. As the research of cognitive psychologist Jonathan Haidt has shown, people asked to defend their purity-based moral judgments reach for logical explanations, but if they’re forced to admit that their explanation has holes, they’ll grope for an alternative one, rather than retracting their initial moral judgment. Logic is merely a fig leaf; disgust is doing all the work.

Although I haven’t seen any studies on it yet, I’m willing to wager that researchers could demonstrate repercussions of another common metaphor: the “argument is war” metaphor, which manifests in the way we talk about “attacking” an idea, “shooting down” arguments, and “defending” a position. Thinking of arguments as battles comes with all sorts of unhelpful baggage. It’s zero-sum, meaning that one person’s gain is necessarily the other’s loss. That precludes any view of the argument as a collaborative effort to find the truth. The war-metaphor also primes us emotionally, stimulating pride, aggression, and the desire to dominate — none of which are conducive to rational discussion.

So far I’ve been discussing implicit metaphors, but explicit metaphors can also lead us astray without us realizing it. We use one thing to metaphorically stand in for another because they share some important property, but then we assume that additional properties of the first thing must also be shared by the second thing. For example, here’s a scientist explaining why complex organisms were traditionally assumed to be more vulnerable to genetic mutations, compared to simpler organisms: “Think of a hammer and a microscope… One is complex, one is simple. If you change the length of an arbitrary component of the system by an inch, for example, you're more likely to break the microscope than the hammer.”
That’s true, but the vulnerable complexity of a microscope isn’t the only kind of complexity. Some systems become more robust to failure as they become more complex, because of the redundancies that accrue — if one part fails, there are others to compensate. Power grids, for example, are built with more power lines than strictly necessary, so that if one line breaks or becomes overloaded, the power gets rerouted through other lines. Vulnerability isn’t a function of complexity per se, but of redundancy. And just because an organism and a microscope are both complex, doesn’t mean the organism shares the microscope’s low redundancy.
Abstinence-only education is a serial abuser of metaphors. There’s one particularly unlovely classroom demonstration in which the teacher hands out candies to her students with the instructions to chew on them for a minute, then spit them back out and rewrap them. She then collects the rewrapped candies in a box and asks a student if he would like to pick one out and eat it. Disgusted, of course, he declines. The message is clear: no one wants “candy” that’s already been tasted by someone else.
In this case, there’s a similarity between the already-chewed candy and a woman who has had previous lovers: both have already been enjoyed by someone else. It’s evident why the act of enjoying a piece of candy diminishes its value to other people. But it’s not evident why the act of sexually enjoying a woman diminishes her value to other people, and no argument is given. The metaphor simply encourages students to extrapolate that property unquestioningly from candy to women.

I came across a great example of misleading metaphors recently via Julian Sanchez, who was complaining about the way policy discussions are often framed in terms of balancing a scale. People will talk about “striking a balance” between goods like innovation and stability, efficiency and equality, or privacy and security. But the image of two goods on opposite ends of a balance implies that you can’t get more of one without giving up the same amount of the other, and that’s often not true. “In my own area of study, the familiar trope of ‘balancing privacy and security’ is a source of constant frustration to privacy advocates,” Sanchez says, “because while there are clearly sometimes trade-offs between the two, it often seems that the zero-sum rhetoric of ‘balancing’ leads people to view them as always in conflict.”
Sometimes, the problem with a metaphor is simply that it’s taken too literally. More than once in a discussion about the ethics of eating animals, someone has told me, “Plants want to live just like animals do, so how can vegans justify eating plants?” The motivation for this point is obvious: if you’re going to be causing suffering no matter what you eat, then you might as well just eat whatever you want. I thought it was risible when I first heard it, but astonishingly, this argument has appeared in the New York Times twice in recent memory — once in December 2009 (“Sorry Vegans: Brussels Sprouts Like to Live, Too”) and then again in March 2011 (“No Face, but Plants Like Life Too”). The articles employ a liberal amount of metaphorical language in describing plants: They “recognize” different wavelengths of light, they “talk” and “listen” to chemical signals, and a plant torn from the ground “struggles to save itself.”
It’s evocative language, but it doesn’t change the fact that plants lack brains and are therefore not capable of actually, non-metaphorically wanting anything. In fact, we use the same sort of language to talk about inanimate objects. Water “wants” to flow downhill. Nature “abhors” a vacuum. A computer “reads” a file and stores it in its “memory.” Since our ancestors’ genetic fitness depended on their sensitivity to each other’s mental states, it feels very natural for us to speak about plants or inanimate objects as if they were agents with desires, wills, and intentions. That’s the kind of thinking we’re built for.
In fact, even the phrase “built for” relies on the implication of a conscious agent doing the building, rather than the unconscious process of evolution. Metaphors are so deeply embedded in our language that it would be difficult, if not impossible, to think without them. And there's nothing wrong with that, as long as we keep a firm grasp — metaphorically speaking — on what they really mean.


  1. There is also an interesting article published in Scienec recently showing how touching inflicene our thoughts in a metaphiric way. For example, considering heavily a candiate for a job is influenced by phsycical weight. Other experiments include texture and temperature. Here is a link to it:


  2. You might be misreading Haidt. Even though the example he uses more often is about incest he doesnt necessarily differentiate between judgments that hinge on variables that lie on the different moral dimensions he defines.That means that disgust judgments are not necessarily more gut-level than harm or fairness ones.The explanation always comes after the judgment. I think you re trying to attribute the one to reason and the other to instinct because you happen to disagree with the latter(you value more hard related judgments rather than disgust).

    Also redundancy isnt a form of complexity per se. That is the information needed to add redundancy is (or might be) much less than the information needed to add the functionality in the first place.

    I hope you realize also how important it is to try and find bad analogies commonly used to justify beliefs you agree with. Theres nothing easier than finding fault with an analogy that supports a view you disagree with. You might also realize you re using analogies much more often than you think (but yours are ok since they re right ;) )

    People use analogies because they take the underlying connection for granted(eg justified by something other than the analogy). When i use an analogy i am not so much trying to convince someone of something as i am trying to explain it.If your opponent disagrees, his gut reaction will be to find a flaw in the analogy just like you did with the examples you gave.

  3. It looks like you're already familiar with Lakoff and Johnson, but because these two books have been such an important part of my life, I want to recommend them to everyone: Metaphors We Live By and Philosophy In the Flesh popularize the theory of conceptual metaphor you've outlined here, explaining it in some detail and showing how it can be applied to philosophical concepts.

    While both of these books may overreach a bit, they're also brilliantly insightful and I recommend them to everyone. The basic ideas in them have become an important part of my own thinking. It's nice to see someone on this sight writing about the importance of metaphorical thought.

  4. An enjoyable and useful read. Thanks.

  5. So, a rhetorical device that has substantial utility can be used purposefully or accidentally to obfuscate concepts. If I want to communicate as clearly as possible I should be aware of this.

    14 paragraphs Julia.


    While I agree with your assessment about the likely motives of conservative arguments against homosexuality, a teleological position (the unnamed logic I assume you're referring to) doesn't necessarily *have holes.* If the person remains philosophically consistent and applies the same line of reasoning to any sexual contact that doesn't or can't directly lead to offspring, including the example of a Christian, married, sterile, heterosexual couple, I don't see how one could deem it faulty. Ridiculous yes, but faulty?

  6. Rather than metaphorical thinking, I'd argue that this is analogous thinking, where metaphors are forms of analogies used to communicate what some refer to as shared abstractions. As with analogies, some are more apt than others, and as with abstractions, others more easily grasp them than some.

  7. Pharisee:

    That teleology wasn't referenced; while it's possible to imagine such a consistently held aversion to non-procreative sex, most of those who oppose homosexual conduct don't seem to be taking their arguments and activism to that logical conclusion. Which makes it reasonable to go looking for explanations other than that of "non-utility", and would indicate faulty reasoning.

  8. @Baron P -- There's really not much difference between how a metaphor and an analogy work, conceptually. The difference is more in how we phrase them ("X is a Y" vs. "X is analogous to Y").

    See, for example, the Wikipedia entry on metaphors: "A metaphor is a figure of speech that constructs an analogy between two things or ideas."

  9. Kostas, you said, "redundancy isnt a form of complexity per se."

    That's what I was saying. My point was that redundancy is what matters if you're concerned with vulnerability, whereas the scientist quoted misleadingly made it seem like complexity is what matters. That's because the complex example he chose happened to also have very low redundancy.

  10. @strangebeasty -- Yes, I enjoyed Lakoff, and actually meant to cite him! But I hadn't heard of Philosophy in the Flesh; thanks for the rec.

  11. @Kostas -- You said, "disgust judgments are not necessarily more gut-level than harm or fairness ones.The explanation always comes after the judgment."

    What distinguishes disgust judgments from harm and fairness judgments is that people don't feel like an explicit "it's gross" is sufficient grounds for a moral judgment, whereas they do feel like "it's unfair" or "it's harmful" are sufficient grounds.

    That's why people end up reaching for other justifications for their purity-based moral judgments.

  12. I think what passes as a sufficient explanation depends only on cultural circumstances and not the type of judgment. The less accepted the judgment the more complex and convoluted the excuse has to be. People feel that incest is universally abhorred so they dont feel like they have to put much effort in justifying their view and therefore no complicated arguments were ever created.The arguments against needn't be any better than the arguments for (well you have to multiply with the proportion of people who are against or for first) If a well organised and populous group starts promoting a pro-incest agenda you ll see anti incest arguments increasing in complexity pretty quickly.

  13. The "plants want to live too" argument does have some merit, I think, in that it ought to stimulate people to think about where they are drawing the line and why. For instance, I know of vegans who eschew honey. Certainly I don't doubt that a bee has more perceptual awareness than a brussel sprout... but it seems to me there is a smaller gap between a bee and a brussel sprout than, say, between a bee and a pig.

    Each person has to make these decisions themselves, of course, but I think it's worth reminding ourselves that (aside from having a more distant common ancestor) there is no magical bright line separating plants from animals. It's okay to eat plants, not because they are plants, but because they don't really experience anything. Do bees? I dunno, really...

  14. Julia, it seems you're trying to tell me what I was earlier trying to tell you - that metaphors are, in short, analogies. My suggested Wikipedia entry for another take on all this is here:

    Also I think you are wrong when you say,
    >The difference is more in how we phrase them ("X is a Y" vs. "X is analogous to Y").<

    Neither a metaphor or an analogy is supposed to be saying X is a Y. Otherwise they'd be synonymous, not analogous.

  15. Julia, I will grant you however that metaphors are more often used deceptively to argue that X is a Y when it isn't.

  16. Fascinating article. As to analogies versus metaphors, my understand has been that metaphors do have the form 'a is P'--though a does not literally have P--and analogies have the form 'a is b as c is to d'. The form 'a is like b' is a simile.

  17. How did someone so young acquire so much information and understanding and wisdom and articulateness?

  18. @Paul
    >The form 'a is like b' is a simile.<

    simile |ˈsiməlē|
    a figure of speech involving the comparison of one thing with another thing of a different kind, used to make a description more emphatic or vivid (e.g., as brave as a lion, crazy like a fox).
    • the use of such a method of comparison.

    Again, a simile is as much concerned with the differences between two things as it is with pointing out the similarities - the things they have in common in spite of the differences.
    In other words there's a hidden premise in a simile that a and b are primarily different.

    With metaphor and analogy, the hidden premises are that a and b are plausibly alike in the context of the particular argument.

    However, I clearly make no claim to being plausibly alike to a logician.

  19. Do you mean to say that we must try not to lose sight of the metaphorest for the trees?

  20. Re 5th Para:

    My clean shirt (which doesn't bother me, in fact pleases me) gets contaminated by something I consider filthy/unclean/bothersome -- thats dirtiness/uncleanliness

    My peaceful conscience gets contaminated by conscience that rebukes and hurts -- thats uncleanliness too (but you may call it immorality)

    I see analogy and in it, parallel constructs. In the end I end up disturbed with either scenarios.

    Not talking of people, but the act....(male homosexual act)....homosexual act, I find equally bothersome. A clean organ in a pouch of feces...not my idea of fun. Just like its not my idea of fun to pack my clean shirt in a sealed bag and throw it in a garbage can even for a few minutes. I can draw more gruesome analogies...but hope that won't be necessary.

    The point is...its all one construct as I see it.

  21. BNJ,
    Perhaps you should never go outdoors without a condom on your head.

  22. Kostas,

    You may want to read up on the marriage practices of the Inca and Hawaiian royalty, the Hapsburg dynasty and various other historical groups. Also, if no "complicated arguments were ever created", where does the current justification to avoid genetic diseases in the children come from? Also, that one is entirely rational, by the way. If it did not exist, there would today certainly be many people arguing for the legalization of sibling marriages - because there would be no harm.


    What homosexual act? Are you referring to a sexual technique that a significant percentage of heterosexual couples practices but that is not even practiced by all homosexuals? Interestingly, if we believe the upper value for the prevalence of homosexuals in western societies as per Wikipedia (13%) and a rather conservative data point for the prevalence of this technique among heterosexuals (given as 20% of all women polled in one study from 1992, the others show higher values), we cannot help but arrive at the conclusion that there are many more heterosexuals performing this "homosexual act" than homosexuals - even if the latter were all male and all performed it, which is clearly not the case, so the ratio is even more skewed towards heteros.

  23. Kostas,


    What homosexual act? Are you referring to a sexual technique that a significant percentage of heterosexual couples practices but that is not even practiced by all homosexuals?"

    Well put. They try to focus on an act, when it is only about similar genitalia.

    Wonder what the hermaphrodites think about all this?

  24. "A clean organ in a pouch of feces...not my idea of fun."

    Your 'clean organ' in a body cavity from whence blood and urine issue forth is perhaps more to your taste?

    And come on 'clean organ'? You mean the one your urine comes out of? Are you perhaps excreting distilled water from there?

    Sex of any kind is pretty messy. You either come to terms with that or remain celibate.

  25. Hi from Tokyo, Japan.
    Amazing post, Julia.
    Metaphors are the basis of the human civilization progress because they are the formats human brains convert somebody's else idea to, in order for them to possibly comprehend it and re-use it.
    (btw comprehend, from the Latin "comprehendere", literally to grasp with)
    I understand a concept by grasping it with a metaphor.
    I think I cannot understand a new idea if I don't construct an internal metaphorical imagery.
    You can only comprehend a new idea if you cross-refer it with your set of previously comprehended ideas and you do it by way of metaphorical reasoning

  26. Julia, isn't there a risk, in discussions like these, that the term "metaphor" becomes itself just a metaphor for imprecise thinking? After all, there are better and worse metaphors, aren't there? And in many cases, a metaphor might be so good that we can learn a great deal from it. So for example, we might develop a metaphor (or analogy if you like) between light waves and water waves. That's not a perfect metaphor, but it's a very good one for explaining things like interference patterns.

    When people say that something is "just a metaphor," they're disregarding all the really great metaphors that have advanced scientific thought over the centuries. They're using "metaphor" to refer only to the sloppy use of metaphors. I think that's a sloppy use of "metaphor."

  27. "If it did not exist, there would today certainly be many people arguing for the legalization of sibling marriages - because there would be no harm."

    Carefully look at the argument here. The fact that people believe it is evidence that your reason is correct? The genetic disease argument is only one possible reason (and I am not convinced that it is the most likely reason why). Certainly there are some recessive genetic diseases that could become more prevalent, but there is no reason to believe that recessive positive traits could not also increase. I don't think that this holds water on the individual level.

    I think that genetic diversity in general is a better explanation... since a highly related groups in a population could more easily be wiped out by changes in their environment... be it infectious disease, weather, famine, etc.

    If what I am saying is correct (which I think is at least a good possibility), then there is a bit of rationlization going on here as well. The genetic disease argument is probably the most common one given, but I'm not sure it is the real "reason."

  28. @Scott -- I do think that poor metaphors are a kind of imprecise thinking, just not the only kind.

    There are certainly better and worse metaphors, and my article wasn't meant to suggest that we should never think metaphorically. That would be, as I wrote, "difficult if not impossible." And they can certainly be a useful way to think -- your example of light waves conceived in terms of water waves is a great one. I just wanted to focus specifically on the ways metaphors can mislead, for the purposes of this article. My goal was to keep that caution in sight, not to get people to stop using metaphors altogether.

  29. @gbboy -- Thanks!

    Also, you might be interested in this forthcoming book, "The Essence of Thought," by Hofstadter and Sander. A friend mentioned it to me in my Facebook wall discussion of this post, and it looks intriguing. I know Hofstadter has written before about how analogies are a central part of thinking; I guess this book will be expanding on that thesis. I signed up to be notified when it comes out.

  30. Dear unpronounceable string of symbols -- That's so kind of you, thanks very much!

  31. How would one "stop using metaphors altogether" when even altogether is a metaphor?

  32. Would a false metaphor be a metaphorgery? One wonders.

  33. @Julia, it would indeed be difficult to abandon metaphor altogether, but that's not really my point. My point is that metaphor isn't the source of the problem at all. If metaphor is such a fundamental part of how we think that we cannot abandon it -- if both our greatest intellectual successes and our greatest intellectual failures involve the use of metaphor -- then I think we must direct our critique at something more specific than metaphor.

  34. @Julia, your essay reminded me of a wonderful metaphor the Wife of Bath uses in _The Canterbury Tales_. Arguing that a husband's pleasure is not diminished by his wife having sex with other men, she compares a jealous husband to someone who refuses to let another person light his torch with the husband's torch because he thinks the fire on his torch will be diminished by doing so. So, one can find metaphors to fight metaphors:

    Christopher Columbus: The world, she's a-round, like an apple.
    Bugs Bunny: The world, she's a-flat, like a pan-a-cake-a.

  35. If perhaps anyone is interested, I have an "idiosyncratic introduction to analogy and metaphor" posted on SSRN: http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1804987

    If you're unable to download it you can contact me via my e-mail address at the Ratio Juris blog and I'll send a copy of the piece (with corrections).


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