The analogy is beautiful for many reasons. For one, they have a few very salient surface similarities (similar properties that don't necessarily involve similar relations), such as being dangerous and deadly, as well as difficult to deal with. Since surface similarities generally drive the retrieval of analogs, it's likely that these surface similarities drive the use of the terrorism-cancer analogy, and that makes the analogy a good illustration of the retrieval stage of analogy. In addition, because the concepts are really broad, and our representations of them rich with relational structure, there are all sorts of directions in which the analogy could go, and thus all sorts of conclusions that we could derive from it. To see this, just look at some of the uses of the analogy a quick google search produced:
- Terrorism is like cancer. Either you deal with it and you cut it out, or it eats
you up. - Itimar Rabinovich
- Certainty is that terrorism is like cancer: it must be rooted out from our history with every means, even if the method does not promise to be painless. This cancer has already reached a metastatic stage. Hence it is our duty not to prevaricate with unproductive, sterile debates in order to avoid the destruction of the little there still is to defend in our world. - Genina Iacabone
- Terrorism is like cancer. Cancer spreads rapidly, and if cells are left to proliferate, they kill their host organism, and thereby kill themselves. There is no reasoning against it. So what do we do about it? - The Real Kato Online
- Terrorism is like cancer. It's starts small then spreads rapidly. - from a comment at Mental Mayhem
- Terrorism is like cancer. You have to eliminate it. Sometimes you use surgery and sometimes radiation. - Lt. Col. William Bograkos, quoted by Ron Jensen in Stars and Stripes
- Terrorism is like cancer, it is both a specific and systemic condition. - William Meyer
- An article titled "Fighting Cancer and Terrorism - Our Fight Is Similar" by Karl Schwartz at Lymphomation.org, of all places. This one compares the two concepts on many different dimensions. Here are two paragraphs:
First, the sickness and unreality we feel at diagnosis is very much like the experience of Americans on September 11 and it's aftermath. The enemy is also similar. It comes from ourselves and is somehow twisted (mutated) to become something that betrays usÂthat seeks our death. Just as every siren post 9-11 evokes renewed fear of assault and senseless violence; every new feeling and symptom carries with it a fear that the cancer is back or growing.
There is no reasoning with this enemy although itÂs theoretically possible to do so, just as itÂs possible to induce cancer cells to differentiate to normal cellsÂbut this change over is rare and not curative. We understand that humanity is a body [another analogy... score!] that requires cooperation and rules of conduct. We know that cancer cells have lost this connectionÂthat they have lost the rules that govern normal function and service to the body.
Of course, some of the parts of the representation of cancer that are carried over to terrorism are pretty general, many other concepts could have been used in place of cancer. For instance, kudzu spreads fast, and if you don't hit it early and often, pretty soon it will be all over the place. Terrorism, then, is like kudzu. Fashion trends spread pretty quickly, too. Terrorism is like fashion trends? It's likely that, at least in some cases, the use of cancer as a base in the analogy is due more to the fact that cancer is really, really bad, and making the comparison reiterates the badness of terrorism (as if this were something of which we needed to be reminded). This illustrates a finding from the research on political analogies: base concepts are often chosen for their emotional valence. If you want to remind people that something is bad, you pick something really bad for your analogy, and if you want to make people feel like something is good, you pick something with positive emotional value. That might be why the "fashion trends" analogy doesn't work well (though I've been known to compare fashion trends to cancer).
It's important to note that the analogies all move in one direction, so I'll say it again: cancer is the base, and is used to tell us something about the target, terrorism. This is important because of one of the most pervasive features of analogy: tasymmetrymetry. Saying X is like Y, and then carrying over information about Y to X, doesn't necessarily make it possible to carry over information from X to Y. asymmetrymetry is part of what makes analogies so useful. The more salient, and extra information in the base domain allows us to make novel inferences about the target domain. The classic examplasymmetrymetry in comparisons, from the work of Amos Tversky, is "North Korea is like Red China." In Tversky's experiments with this comparison, participants judged North Korea to be much more similar to China than China is to North Korea. This is, in part, because the properties that drive the comparison between the two are more salient in China than in North Korea. That's why people chose China as the base concept in the comparison in the first place, and is likely one of the reasons why people chose cancer as a base concept in the terrorism-cancer analogy. In addition, it's likely that participants' representations of China were richerichar than their representations of North Korea. This means there were a wealth of candidate inferences from China to North Korea, and few, if any, from North Korea to China. Most of those candidate inferences probably wouldn't hold for North Korea, but the analogy makes it possible to test them out if we're so inclined. The same is probably true of the terrorism-cancer analogy. As the few examples above show, we can try inferences from several different parts of our cancer representation, including treatment, the behavior of cancer at large and individual cancer cells, and even how people feel when they find out that they have cancer. It's not clear from those comparisons, however, which if any inferences we might draw from terrorism to cancer. Thus, contrary to what one ofcommentersntors on Quiggin's posts asserts, the assertion that "terrorism is like cancer" does not imply the assertion that "cancer is like terrorism," or at least, not that cancer is like terrorism in the same way or to the same degree.
One other interesting, and common, feature of the above comparisons (except, perhaps, Meyer's strangely-placed article) is how narrow the comparisons are. Each author aligns the representations of terrorism and cancer on only a few of the many possible relations in each of the concepts' representations. The analogy, while it is likely meant to carry some emotional weight, isn't meant to be a very deep one. It's just used to say one or two things about terrorism using facts about cancer. It's not quite fair, then, to criticize the uses of the analogy by pointing out that the analogy itself fails if we try to extend it to other parts of the cancer representation, which is part of what Quiggin appears to be doing. Of course, Quiggin's own use of the analogy serves a pretty clear rhetorical purpose, and serves it well. In a sense, what he does is hypothetically reversecomparisonrsion, so that it is now cancer is like terrorism, and he then shows how aspects ofrepresentationntion of terrorism, or the discourse on terrorism, either don't carry over to cancer, or look really silly when they do. Using an opponent's analogy against him or her in order to show the absurdity of his or her position is yet another demonstration of a common use of analogy.
So, while the analogy may not be very good, or very useful for reasoning about terrorism (I'm not sure any of the things people said in the above examples were unknown to their audiences before they read the analogy), I'd bet it's a pretty effective analogy from a communication standpoint, and from the perspective of an analogy hunter like me, it's wonderful, because it perfectly illustrates so many aspects of analogy's production, use, and comprehension. I wish I'd run across it sooner.