Mere addition paradox
Encyclopedia
The mere addition paradox is a problem in ethics
, identified by Derek Parfit
, and appearing in his book, Reasons and Persons
(1984). The paradox identifies apparent inconsistency between three seemingly true beliefs about population ethics
by arguing that utilitarianism
leads to an apparent overpopulated dystopian world.
represented by column height. For simplicity, in each group of people represented, everyone in the group has exactly the same level of happiness, though Parfit did not consider this essential to the argument.
In situation A, everyone is happy.
In situation A+, there are the extra people. There is the same population as in A, and another population of the same size, which is less happy, but whose lives are nevertheless worth living. The two populations are entirely separate, that is, they cannot communicate and are not even aware of each other. Parfit gives the example of A+ being a possible state of the world before the Atlantic was crossed, and says that A, in that case, represents an alternative history in which the Americas
had never been inhabited by any humans.
In situation B-, there are again two separate populations, of the same size as before, but now of equal happiness. The increase in happiness of the right-hand population is greater than the decrease in happiness of the left-hand population. Therefore, average happiness in B- is higher.
Finally in situation B, there is a single population whose size is the sum of the two populations in situation B-, and at the same level of happiness.
Furthermore, there are the same numbers of people on both sides of the divide in situation B- as there are in situation A+. The average happiness in B- is higher than A+ (though lower than A). Since A+ and B- have the same number of people, and because there is a greater level of equality and average happiness in B-, it seems that, all things considered, B- is better than A+. But the situations B- and B are the same, except the communication gap is removed. It seems that B is at least as good as B-.
to say otherwise. This is a contradiction, but it is not clear how to avoid it.
, meaning that our assertion that B- is better than A by way of A+ is not justified—it could very well be the case that B- is better than A+, and A+ is better than A, and yet A is better than B-. This is of course incompatible with any form of utilitarianism. Temkin
argues for this approach.
The paradox can be defeated by asserting that A+ is actually worse than A, in other words, that adding people of less-than-average happiness into the world makes the overall situation worse. This is the conclusion of "average utilitarianism"
, which aims at maximizing average happiness. However, this solution may commit one to the position that it is actually bad for people of less than average happiness to be born, even if their lives are worth living.
Another position might argue for some threshold above the level at which lives become worth living, but below which additional lives would nonetheless make the situation worse. Parfit argues that for this position to be plausible, such a threshold would be so low as to apply only to lives that are "gravely deficient" and which, "though worth living ... must be crimped and mean." Parfit calls this hypothetical threshold the "bad level," and argues that its existence would not resolve the paradox because population A would still be better than an enormous population with all members having lives at the "bad level."
Parfit also considers an objection where the comparison between A+ and B- is attacked. The comparison between A and A+ was partly dependent on their separation. Thus A+ and B- might simply be incomparable. Parfit gives the Rich and Poor example, in which two people live in separate societies, and are unknown to each other, but are both known to you, and you have to make a choice between helping one or the other. Thus, despite their separation, it is meaningful to ask whether A+ is better than B- or not. One could deny that B- is better than A+, and therefore neither is B. But this rejection implies that what is most important is the happiness of the happiest people, and commits one to the view that a smaller decrease in the happiness of the happiest people outweighs a bigger increase in the happiness of less happy people, at least in some cases. Parfit calls this the Elitist view.
Of course one can simply accept the Repugnant Conclusion. Torbjörn Tännsjö
argues that we have a false intuition of the moral weight of billions upon billions of lives "barely worth living". He argues that we must consider that life in Z would not be terrible, and that in our actual world, most lives are actually not far above, and often fall below, the level of "not worth living". Therefore the Repugnant Conclusion really isn't so repugnant.
Ethics
Ethics, also known as moral philosophy, is a branch of philosophy that addresses questions about morality—that is, concepts such as good and evil, right and wrong, virtue and vice, justice and crime, etc.Major branches of ethics include:...
, identified by Derek Parfit
Derek Parfit
Derek Parfit is a British philosopher who specializes in problems of personal identity, rationality and ethics, and the relations between them. His 1984 book Reasons and Persons has been very influential...
, and appearing in his book, Reasons and Persons
Reasons and Persons
Reasons and Persons is a philosophical work by Derek Parfit, first published in 1984. It focuses on ethics, rationality and personal identity....
(1984). The paradox identifies apparent inconsistency between three seemingly true beliefs about population ethics
Population ethics
Population ethics is the philosophical study of the ethical problems concerning population.-External links:** in the Stanford Encyclopedia of Philosophy...
by arguing that utilitarianism
Utilitarianism
Utilitarianism is an ethical theory holding that the proper course of action is the one that maximizes the overall "happiness", by whatever means necessary. It is thus a form of consequentialism, meaning that the moral worth of an action is determined only by its resulting outcome, and that one can...
leads to an apparent overpopulated dystopian world.
The Paradox
The paradox arises from consideration of four different possibilities. The following diagrams show different situations, with each bar representing a population. The group's size is represented by column width, and the group's happinessHappiness
Happiness is a mental state of well-being characterized by positive emotions ranging from contentment to intense joy. A variety of biological, psychological, religious, and philosophical approaches have striven to define happiness and identify its sources....
represented by column height. For simplicity, in each group of people represented, everyone in the group has exactly the same level of happiness, though Parfit did not consider this essential to the argument.
In situation A, everyone is happy.
In situation A+, there are the extra people. There is the same population as in A, and another population of the same size, which is less happy, but whose lives are nevertheless worth living. The two populations are entirely separate, that is, they cannot communicate and are not even aware of each other. Parfit gives the example of A+ being a possible state of the world before the Atlantic was crossed, and says that A, in that case, represents an alternative history in which the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
had never been inhabited by any humans.
In situation B-, there are again two separate populations, of the same size as before, but now of equal happiness. The increase in happiness of the right-hand population is greater than the decrease in happiness of the left-hand population. Therefore, average happiness in B- is higher.
Finally in situation B, there is a single population whose size is the sum of the two populations in situation B-, and at the same level of happiness.
Going from A to B
The difference between the situations A and A+ is only in the existence of extra people at a lower level of happiness. If the two populations were known to each other, and were aware of the inequality, this would arguably constitute social injustice. However, as they do not, Parfit says this represents a Mere Addition, and it seems implausible to him that it would be worse for the extra people to exist. Thus, he argues, A+ is not worse than A.Furthermore, there are the same numbers of people on both sides of the divide in situation B- as there are in situation A+. The average happiness in B- is higher than A+ (though lower than A). Since A+ and B- have the same number of people, and because there is a greater level of equality and average happiness in B-, it seems that, all things considered, B- is better than A+. But the situations B- and B are the same, except the communication gap is removed. It seems that B is at least as good as B-.
The Repugnant Conclusion
We can then repeat the argument, and imagine another divide, and ask if it would be better for more extra people to exist, unknown to the people in B, and so on, as before. We then arrive at a situation C, in which the population is even larger, and less happy, though still with lives worth living. And if we agree that B is not worse than A, then we would conclude in the same fashion that C is not worse than B. But then we could repeat that argument again, finally arriving at a situation Z, in which there are an enormous number of people whose lives are worth living, but just barely. Parfit calls this the Repugnant Conclusion, and says that Z is in fact worse than A, and that it goes against what he believes about overpopulationOverpopulation
Overpopulation is a condition where an organism's numbers exceed the carrying capacity of its habitat. The term often refers to the relationship between the human population and its environment, the Earth...
to say otherwise. This is a contradiction, but it is not clear how to avoid it.
Criticisms and responses
The paradox is immediately resolved by the conclusion that the "better than" relation is not transitiveTransitive relation
In mathematics, a binary relation R over a set X is transitive if whenever an element a is related to an element b, and b is in turn related to an element c, then a is also related to c....
, meaning that our assertion that B- is better than A by way of A+ is not justified—it could very well be the case that B- is better than A+, and A+ is better than A, and yet A is better than B-. This is of course incompatible with any form of utilitarianism. Temkin
Larry Temkin
' is an American philosopher specializing in normative ethics and political philosophy. His research into equality, practical reason, and the nature of the good has been very influential. His work on the intransitivity of the all things considered better than relation is groundbreaking and...
argues for this approach.
The paradox can be defeated by asserting that A+ is actually worse than A, in other words, that adding people of less-than-average happiness into the world makes the overall situation worse. This is the conclusion of "average utilitarianism"
Average and total utilitarianism
All proponents of utilitarianism believe that the quality of conscious experience is important; indeed it is the basis of their consequentialist approach to ethics. However, it is unclear what it is that is supposed to be maximized: average happiness or total happiness...
, which aims at maximizing average happiness. However, this solution may commit one to the position that it is actually bad for people of less than average happiness to be born, even if their lives are worth living.
Another position might argue for some threshold above the level at which lives become worth living, but below which additional lives would nonetheless make the situation worse. Parfit argues that for this position to be plausible, such a threshold would be so low as to apply only to lives that are "gravely deficient" and which, "though worth living ... must be crimped and mean." Parfit calls this hypothetical threshold the "bad level," and argues that its existence would not resolve the paradox because population A would still be better than an enormous population with all members having lives at the "bad level."
Parfit also considers an objection where the comparison between A+ and B- is attacked. The comparison between A and A+ was partly dependent on their separation. Thus A+ and B- might simply be incomparable. Parfit gives the Rich and Poor example, in which two people live in separate societies, and are unknown to each other, but are both known to you, and you have to make a choice between helping one or the other. Thus, despite their separation, it is meaningful to ask whether A+ is better than B- or not. One could deny that B- is better than A+, and therefore neither is B. But this rejection implies that what is most important is the happiness of the happiest people, and commits one to the view that a smaller decrease in the happiness of the happiest people outweighs a bigger increase in the happiness of less happy people, at least in some cases. Parfit calls this the Elitist view.
Of course one can simply accept the Repugnant Conclusion. Torbjörn Tännsjö
Torbjörn Tännsjö
Torbjörn Tännsjö is a Swedish professor of philosophy. He has held a chair in Practical Philosophy at Stockholm University since 2002 and he is Affiliated Professor of Medical Ethics at Karolinska Institute...
argues that we have a false intuition of the moral weight of billions upon billions of lives "barely worth living". He argues that we must consider that life in Z would not be terrible, and that in our actual world, most lives are actually not far above, and often fall below, the level of "not worth living". Therefore the Repugnant Conclusion really isn't so repugnant.
See also
- Average and total utilitarianismAverage and total utilitarianismAll proponents of utilitarianism believe that the quality of conscious experience is important; indeed it is the basis of their consequentialist approach to ethics. However, it is unclear what it is that is supposed to be maximized: average happiness or total happiness...
- Carrying capacityCarrying capacityThe carrying capacity of a biological species in an environment is the maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water and other necessities available in the environment...
and ecological footprintEcological footprintThe ecological footprint is a measure of human demand on the Earth's ecosystems. It is a standardized measure of demand for natural capital that may be contrasted with the planet's ecological capacity to regenerate. It represents the amount of biologically productive land and sea area necessary to... - A Theory of JusticeA Theory of JusticeA Theory of Justice is a book of political philosophy and ethics by John Rawls. It was originally published in 1971 and revised in both 1975 and 1999. In A Theory of Justice, Rawls attempts to solve the problem of distributive justice by utilising a variant of the familiar device of the social...
by John RawlsJohn RawlsJohn Bordley Rawls was an American philosopher and a leading figure in moral and political philosophy. He held the James Bryant Conant University Professorship at Harvard University.... - MinimaxMinimaxMinimax is a decision rule used in decision theory, game theory, statistics and philosophy for minimizing the possible loss for a worst case scenario. Alternatively, it can be thought of as maximizing the minimum gain...
- OverpopulationOverpopulationOverpopulation is a condition where an organism's numbers exceed the carrying capacity of its habitat. The term often refers to the relationship between the human population and its environment, the Earth...
- Utility monsterUtility monsterThe utility monster is a thought experiment in the study of ethics. It was created by philosopher Robert Nozick in 1974 as a criticism of utilitarianism....
- Sorites ParadoxSorites paradoxThe sorites paradox is a paradox that arises from vague predicates. The paradox of the heap is an example of this paradox which arises when one considers a heap of sand, from which grains are individually removed...
External links
- The Repugnant Conclusion (Stanford Encyclopedia of PhilosophyStanford Encyclopedia of PhilosophyThe Stanford Encyclopedia of Philosophy is a freely-accessible online encyclopedia of philosophy maintained by Stanford University. Each entry is written and maintained by an expert in the field, including professors from over 65 academic institutions worldwide...
) - Alex Tabarrok's The Philosophical Cow (an application to the animal rightsAnimal rightsAnimal rights, also known as animal liberation, is the idea that the most basic interests of non-human animals should be afforded the same consideration as the similar interests of human beings...
issue)