A long time ago, I mentioned something here about contractarian and utilitarian philosophies, and someone asked me what the difference was. That seemed a long essay, so I put it off. Now I've thought of an example that should illustrate the difference succinctly, so I'm finally ready to answer. I'll start with brief descriptions of the philosophies, then I'll give the example.
Utilitarianism is about maximizing "utility" - roughly speaking, happiness - over all people. According to utilitarianism, resources should be distributed in a way that maximizes the total happiness of everyone. Sometimes this is described as "the greatest good for the greatest number", though that's an approximation that is not mathematically rigorous.
Contractarian philosophy, in contrast, focuses on the voluntariness of exchanges. According to contractarian philosophy, resources should be redistributed only in voluntary ways, such as through agreements or contracts, rather than through coercion or force.
Now for our example. Let's imagine two toddlers, siblings, Duncan and Margaret. They both like Chinese fortune cookies, but Duncan likes them more than Margaret does. After a visit to a Chinese restaurant, they each get a fortune cookie. Duncan eats his immediately. The question is what happens to Margaret's fortune cookie. We examine three possibilities.
The first possibility is that Margaret eats her fortune cookie. The second possibility is that Duncan takes Margaret's fortune cookie from her and eats it before Margaret can get it back. The third possibility is that Margaret voluntarily gives her fortune cookie to Duncan, who then eats it.
The third possibility is fine from both the utilitarian and the contractarian standpoints: Duncan gets more enjoyment from the fortune cookie than Margaret does, so total utility is maximized, while Margaret gives up the fortune cookie voluntarily, satisfying the contractarian prohibition on force.
However, not all toddlers are always willing to forgo enjoying their yummy delicious fortune cookies, just because other toddlers find fortune cookies even more yummy and delicious. Thus, we must also examine the first and second possibilities.
In the first possibility, Margaret simply keeps and eats her fortune cookie; since no resource transfer, let alone force or coercion, is involved, this possibility is just as acceptable as the third possibility from a contractarian standpoint. From a utilitarian standpoint, however, it is not acceptable. The fortune cookie would produce more happiness if Duncan ate it; thus, Duncan should have it, and Margaret is being selfish for keeping it.
In the second possibility, Duncan eats the fortune cookie after taking it; the resource distribution is the same as in the third possibility, where the fortune cookie is given to him to eat, so they are equally acceptable from a utilitarian standpoint. From a contractarian perspective, however, Duncan's use of force makes the situation unjust, and Duncan is being greedy for taking the cookie from Margaret.
I think that example captures well the basic difference between utilitarian and contractarian philosophical approaches. For more detailed utilitarian approaches, see the work of Thomas More or, more recently, John Rawls; for contractarian approaches, see John Locke or Robert Nozick.
This strikes me as being the same sort of reasoning flaw as when people use the prisoner's dilemma when the correct case is the repeated prisoner's dilemma.
From a utilitarian standpoint, if Duncan takes the cookie by force this time, the next time Margaret has a cookie she will expend resources to defend her possession of it, whether by eating it immediately even though she would like it more if she ate it when she wasn't so full, hiding it (with the attendant possibility of losing it, etc.) Furthermore, if Margaret is aware of the saying 'the best defense is a good offense' or even if she wishes revenge for the lost of her cookie the time, there is a chance the kids will enter into a negative sum game for quite some time.
So when considering things for a utilitarian perspective, choosing the appropriate time span for considering consequences is important.
Possibly. On the other hand, an optimistic utilitarian can hope that if Margaret gets her cookie snatched away enough times, she'll learn to resist less and less until she gives it up freely. That seems to be what most utilitarians think ought to happen.
And who is to say that the kids don't enjoy conflict, making fighting a positive sum game?