Derek Parfit - The Future

The Future

Parfit's most famous postulations come in Part IV of Reasons and Persons, where he discusses possible futures for the world. He shows that, in the discussion of possible futures, both average and total utilitarian standards lead to unwelcome conclusions. Applying total utilitarian standards (absolute total happiness) to possible growth paths of population and welfare leads to what he calls the Repugnant Conclusion. Parfit illustrates this with a simple thought experiment. Imagine a choice between possible futures. In A, 10 billion people would live during the next generation, all with extremely happy lives, lives far happier than anyone's today. In B, there are 20 billion people all living lives that, while slightly less happy than those in A, are still very happy. Under total utility maximization we should prefer B to A, and through a regressive process of population increases and happiness decreases (in each pair of cases the happiness decrease is more than outweighed by the population increase) we are forced to prefer Z, a world of hundreds of billion people all living lives barely worth living, to A. Even if we do not hold that coming to exist can benefit someone, we still must at least admit that Z is no worse than A.

Parfit makes a similar argument against average utilitarian standards. If all we care about is average happiness, we are forced to conclude that an extremely small population, say ten people, over the course of human history is the best outcome if we assume that these ten people (Adam and Eve et al.) had lives happier than we could ever imagine. Then consider the case of American immigration. Presumably alien welfare is less than American, but the would-be alien benefits tremendously from leaving his homeland. Assume also that Americans benefit from immigration (at least in small amounts) because they get cheap labor, etc. Under immigration both groups are better off, but if this increase is offset by increase in the population, then average welfare is lower. Thus although everyone is better off, this is not the preferred outcome. Parfit asserts that this is simply absurd.

Parfit then moves to discuss the identity of future generations. He first posits that one's existence is intimately related to the time and conditions of conception. I would not be me if my parents waited two more years to have a child. While they would still have had a child, he would certainly have been someone else; even if he had still been their first-born son, he would not have been me.

Study of weather patterns and other physical phenomena in the 20th century has shown that very minor changes in conditions at time T have drastic effects at all times after T. Compare this to the romantic involvement of future childbearing partners. Any actions taken today, at time T, will affect who exists after only a few generations. For instance, a significant change in global environmental policy would shift the conditions of the conception process so much that after 300 years none of the same people that would have been born are in fact born. Different couples meet each other and conceive at different times, and so different people come into existence. This is known as the 'non-identity problem'.

We could thus craft disastrous policies that would be worse for nobody, because none of the same people would exist under the different policies. If we consider the moral ramifications of potential policies in person-affecting terms, we will have no reason to prefer a sound policy over an unsound one provided that its effects are not felt for a few generations. This is the non-identity crisis in its purest form: the identity of future generations is causally dependent, in a very sensitive way, on the actions of the present generations. Philosophers have long ignored this problem and devised systems of ethics that are powerless against our temporally biased policies.