Little heard of in non-philosophical circles, the non-identity problem is one of the main problems in discussing harm in intergenerational justice. It was the most stringently formulated by Derek Parfit. The non-identity problem is one of those problems that seem trivial at first, but the longer you think about them, the more it grows on you until you are utterly devastated and hopeless because all solutions to it seem unsatisfactory. In this posting I want to introduce the problem and discuss some of its complexities.
First to the sex. The problem has to do with the narrow window of conception for each person on this planet. If parents conceive a child a month earlier or later, it will be a different child, as it will come from different sperm and egg. So, if your parents would not have had sex at a particular time under particular circumstances, you would never have been born, as they would have conceived a different child.
Therefore, if the circumstances of conception are leading to you being in a bad state, you cannot say that they harmed you (as long as you live a life that is worth living), as the alternative to you being conceived under those circumstances would be non-existence, which has no value.
So let’s imagine you were conceived during a Rolling Stones concert and your parents (of course hypothetically) had a blast under the influence of drugs, which leads to you developing poor health once you are born. Aside your poor health, you live a life that is worth living. Based on the non-identity problem you cannot said to have been harmed as the alternative for you would be not living at all, so you can be no worse off than under the alternative.
Clearly, this sounds very counterintuitive as most people would claim that they might have a legitimate complaint because of their parent’s reckless behavior. But as long as we stick to a conception of harm that ascribes harm to a particular person and that compares the harmful action with a non-harmful alternative (for example, if you punch my nose after reading this article, we will define the harm done to me based on comparison to a hypothetical scenario where you would have not punched me and my nose would still be intact), there seems no really good way out of this problem.
What makes the problem even larger is that it can be applied to policies or major societal decisions, such as for example the use of fossil fuels to power our economy – which, as you might guess, makes it relevant to climate change. Parfit, for example, provides the example of a risky policy, where persons are harmed three centuries after our action because of a risky energy policy we took by burying nuclear waste. As the policy leads to different people living in the future who would have never existed without the policy (and as their life is worth living even with the catastrophe), Parfit notes that they are not worse off because of this policy.
So next time you complain about your parents or the world, think deeply if you could really have been harmed by them or if it is a case of the non-identity problem.
I think this is a good point to stop. Give the problem some time to sink in …
In my next posting I will discuss some possible suggestions to solve the non-identity problem.
 Parfit, D. (1984). Reasons and Persons. Oxford: Clarendon Press.