We reach the so-called Repugnant Conclusion when considering the Mere Addition Paradox. See Wikipedia's entry for a good definition of the paradox, or my shortened version as follows:

Population A is made up of a number of people with a high quality of life, and high levels of happiness. Imagine a second population, A+, which is identical to A apart from the addition of some extra people who are less happy than those in A, but whose lives are still certainly worth living. We can all agree that, to the outside observer, A+ is no worse than A as a general state of affairs.

Now imagine a population B, with the same number of people as in A+, all at a constant happiness lower than than of A, but higher than that of the average in A+. Certainly B, to the outside observer, is no worse than A+.

Since A+ is no worse than A, and B is no worse than A+, it follows that B is no worse than A. Follow the same argument to C and D and E and so on, and we end up with the "Repugnant Conclusion", namely that it is no worse to have an enormous population of people whose lives are barely (but they are just) worth living, than to have a smaller population with truly wonderful lives.

Many attempts have been made to sort out this mess, of which a great number are based in the details of better and worse, average and total, repugnant or acceptable, transitive or non-transitive. All such attempts to deal with the fallout of the Repugnant Conclusion miss the point. They look at a crossword into which the last clues don't fit and assume a mistake earlier in their working. They spend years tinkering with the earlier clues to try and fit them into an acceptable conclusion. They miss the point that the Mere Addition Paradox is fundamentally flawed. It is an interesting thought experiment, but not a paradox. The whole problem is based on the idea that one situation can be intrinsically better than another, from some point of view other than that of any individual involved in it. On what basis is this idea put forward? The foundation is the idea of objective ethics. No solid ground there.

The only practical purpose of studying or thinking about ethics or philosophy (other than the pure pleasure of intellectual pursuit) is surely to develop a framework in which to make better informed decisions and judgements about the situations we are placed in. Saying that B is no worse than A begs the question - what do we mean by worse? Nothing is the only sensible answer to that. So what are we to make of it?

Consider yourself as an average member of the population in A. You and all your family, friends, acquaintances and so on live happily. Would you change to A+? You wouldn't mind either way. You and your kin have the same level of happiness as before. Why not? Now you are in A+, and you have the level of happiness of the original As. Would you change to B? Absolutely not. You are being presented with a decrease in your levels of happiness. From your point of view B is definitively worse.

Consider yourself as an average member of the pluses in A+. You and all your family, friends, acquaintances and so on live reasonably happily. Would you change to B? Absolutely. You are being presented with a increase in your levels of happiness. Easy.

Consider yourself as an average member of B. Would you change to A+? Well that depends which part of the population you would become...

These are the only ways to judge better or worse.

A simplistic model such as that which generates the Repugnant Conclusion misses the point entirely. As a member of A, you might well feel that knowing you are increasing the happiness of the pluses would in turn make you happier. This is where the (absolutely essential) element of pleasure in others' happiness should come in. This would be a perfectly good reason for changing from A to B, if it weren't for the fact that the constraints of the model automatically mean that your happiness must go down. Such simple models, when considered from the perspective of a participant, deny the possibility of an individual's enjoyment of others' pleasure.

The conclusion is not repugnant. There is in fact no conclusion. The real use of such thought experiments as the Mere Addition Paradox is to highlight the assumptions implicit in the words 'better', 'worse', 'desirable', 'repugnant' and so on.

Giles Hayter
London
February 2009