The Language of Causation

One of the great verbal tricksters in English is the word cause, especially when used as a noun with the definite article the, as in a sentence like (1), which is clearly false.

(1) Smoking is the cause of lung cancer.

Even occurrences of the indefinite article a when it occurs in a sentence like (2) are problematic. This sentence suggests that smoking all by itself can cause cancer which is surely false..

(2) Smoking is a cause of cancer.

The same is true of generic verb occurrences of cause, as in (3).

(3) Smoking causes lung cancer.

If you are head of a tobacco company being sued you will want people to make claims like (1),(2), and (3) since none of them stands any chance of being true. Though they are used very frequently, such claims as these are very easily falsified because every event or state of affairs will normally have multiple causes. In the case of smoking, ones genetic make up has a bearing on whether or not a person will get lung cancer. Environmental factors are likely to play a role as well.

What makes generic claims so tricky is that we readily assent to a claim like (4) even though we know that more than half of the lion population, namely the females and the cubs, don't have manes.

(4) Lions have manes.

Similarly, even though (3) makes the very strong claim that smoking alone can cause cancer, it is consistent with some people being life-long smokers and never contracting lung cancer. That is, it is consistent with (6).

(6) Smoking doesn't always cause lung cancer.

This is the beauty of generic claims -- they make very strong (because highly general) claims but they aren't falsified by counterexamples. They live a good life, as the lives of propositions go.

I ran across a number of claims containing "not the cause of" such as

(7) HIV Is Not the Cause of AIDS
(8) Cosmic Rays Are Not the Cause of Climate Change, Scientists Say
(9) Income inequality is not the cause of this nation's social problems.
(10) Gun ownership is not the cause of America's high murder rate.

The last two come from the same web site and are quite comical. Only an idiot would claim that income inequality is THE cause of the nation's social problems or even worse that gun ownership is THE cause of America's high murder rate. Obviously, for a murder to occur, the gun owner will have to load the gun, take the safety off, point it accurately at the intended victim, and pull the trigger and do all of this with the intent to kill (at least for first degree murder) so we know that gun ownership simpliciter does not cause murder. Moreover, there are causes of murder not involving guns such as strangling someone with ones hands or using a garrote or knifing someone to death (cf the O. J. Simpson murder trial) or running them over with a car or whacking them with a baseball bat and etc.

The eighth claim is more interesting. The claim at issue is this one

In July 2003, astrophysicist Nir Shaviv and geologist Jan Veizer wrote in GSA Today that they had established a correlation between cosmic rays and temperature evolution over hundreds of millions of years. They also claimed that current global warming is not primarily caused by human emissions of carbon dioxide. Their findings have been widely reported in international news media.

Notice first that (8) is actually the headline for a news release and was almost surely composed by a PR guy/gal, not an actual scientist. Moreover, the passage quoted does not provide support for the idea that cosmic rays are THE cause of climate change. All the scientists seem to have established, if they established anything, was "a correlation between cosmic rays and temperature evolution over hundreds of millions of years. [emphasis added]" I don't know whether these scientists said anything like "current global warming is not primarily caused by human emissions of carbon dioxide [emphasis added]" but this kind of claim is of interest as well. Scientists who ought to know better say things like "the primary reason for X is Y" or "the real reason for X is Y." I suspect I have used both in the past. These are naughty claims. When you have a set of causes of some event Y, how do you establish one of them as the primary one? [At this point I might have gone into Aristotle's four causes but I have been warned against having overlong blogs.]

As sentient beings who are proud of our mental possessions, we tend to attach great importance to our decisions and actions as event movers and shakers. But there are always other factors. When, as in the case of cosmic rays, there are no human sentient beings involved religious people will sometimes evoke God's choosing to subject us to his/her wrath by, say, raining cosmic rays onto us. Jerry Falwell once said, for instance, "AIDS is not just God's punishment for homosexuals; it is God's punishment for the society that tolerates homosexuals." Who knew? I thought it was a virus. We have to expect that from God, I suppose, for as Archibald McLeish wrote in his play JB "If God is God, God is not good. If God is good, God is not God."

Right now, plaintiff's lawyers are going after Merck and its product, Vioxx. In this and in all other liability cases, I suspect, the issue of who caused what and the relative importance of different causes lie at the heart of the suit. I picked up the following collection of sentences from the article linked to the title of this blog. There is not just the headline (11), but also (12)-(17), for you to entertain yourself with.

(11) Cardiologist: Vioxx did not cause postal worker's heart attack.
(12) A postal worker who suffered a heart attack had a buildup of plaque in his arteries that was not caused by the since-withdrawn painkiller Vioxx,...
(13) ...only minimal plaque buildup is needed to cause the "small, modest" heart attack...
(14) Humeston, 60, is suing Vioxx maker Merck & Co., blaming his heart attack on intermittent use of the drug over two months.
(15) The plaque broke off, causing Humeston's heart attack, he said.
(16) ... Tyberg testified that Vioxx does not cause plaque buildup.
(17) "Did Mr. Humeston have sufficient plaque in his arteries to cause a heart attack?" Sullivan asked.

This gives you a taste of how loosely "cause" and what we might call "causal words" such as "blame," as in "X blames Y on Z," were used in the article and in court. Not a single one of these uses is intellectually respectable. Even (15) doesn't attribute the attack to what Aristotle might have called "the final cause" -- that would have been, the obstruction of blood flow. It could be that narrowed arteries at the point the clot lodged itself played a role as well. Perhaps the best guidance for us is to drop the word "cause" from our vocabularies. The chances are that nothing good will come from their use.

Tags: language, causation, reasoning