Contrary to popular belief, the concept of causation is actually extraordinarily tricky. Once we step out of hard physical sciences (and perhaps even then), attributing a cause to an effect becomes a very difficult matter. Here I go over some of the problems with showing causation and look specifically at the “cause” of poverty.

The first problem with showing causation is that sometimes multiple things need to occur simultaneously for some effect to be realized. That is, there are multiple necessary conditions. For example, perhaps A, B, and C need to happen for D to result. In such cases, if you stop A from happening, then by definition D wont result. Upon observing this, people often conclude — through either hasty or opportunistic reasoning — that A is the cause of D. After all, without A, D is not possible. But under that reasoning, B and C are also the causes of D: if you stop either one from happening, D fails to materialize. In the case of multiple necessary conditions, you cannot point to a cause; you can only point to a number of conditions that must necessarily come together simultaneously for some effect to result.

The second problem is that sometimes multiple things can each be sufficient to cause some effect. This is called overdetermination. An abstract example would be this: A by itself could cause D, B by itself could cause D, and A and B both happen. A concrete example would be this: I watered my lawn, and it rained, and the lawn is wet. What would you say actually caused my lawn to be wet? If I didn’t water it, it would still be wet. So you might say the rain. But if it didn’t rain, it would also still be wet, leading you to say that my watering of the lawn is the cause. As with the first problem, overdetermination makes it impossible to coherently talk about the cause, but people do it anyways.

There are two main problems that occur when folks — especially on the right wing — start talking about the cause(s) of poverty. The first falls under the overdetermination problem above. Right-wingers will often blame poverty on things like drugs, single parenting, and crime. But as Noah Smith pointed out recently, there are places in this world that have very low rates of those and have high levels of poverty, e.g. Japan.

Now it is possible that drug use and crime are reactions to poverty, and not their cause, a point Smith brings up. But even if we ignore that criticism, what Smith’s post points to is that, at minimum, poverty has multiple sufficient causes. That is, even if we believe that drug use and crime are sufficient by themselves to cause poverty, that does not mean eliminating either is sufficient to end poverty. If other sufficient causes are also present (and we have poverty overdetermination), then poverty will still persist, just as the lawn is still wet if I don’t water it.

Noting that poverty is overdetermined is actually far too charitable to right wing points about poverty. As far I can tell, the causes the right wing gives are neither necessary nor sufficient to cause poverty. You can have poverty without drug use, crime, or single parenting, meaning they are not necessary for poverty to exist (that is what Noah Smith’s post is about). And you can have no poverty with drug use, crime, and single parenting, meaning that these are not even sufficient causes. How? Give poor people money, including the drug users, the single parents, and the criminals. You might not like that policy, but you cannot deny that it would eliminate poverty: it would do so by definition.

Given the possibility of cash transfers, you can never point to something as the cause of poverty. There is always at least one other necessary condition for that poverty to exist, i.e. a policy of not transferring enough money to poor people to make them not poor. So, the best the right-wing can do is say “assuming we just refuse to do the cash transfer thing, X is a sufficient cause of poverty, but eliminating X wont reduce poverty because poverty is probably overdetermined anyways.” In short, discussions of the causes of poverty are generally incoherent nonsense, and typically only serve the goal of preserving the status quo.