The Argument from Overpopulation—Logical and Ethical Considerations Jesper Ryberg

A traditional subject for discussion in population debates is whether the world or any subdivisions of it are overpopulated. Some proclaim that we are indeed in a state of overpopulation, while others persistently deny this claim. However, statements which proclaim or deny overpopulation are almost never accompanied by satisfactory definitions as to what overpopulation means. This is most unsatisfactory, especially because whether or not overpopulation is a fact is often claimed to be crucial when it comes to the justification of population political recommendations. This article considers an argument from overpopulation, according to which overpopulation justifies policies which reduce population size; and an argument against overpopulation, according to which the fact that present problems can be handled without population reductions establishes that there is no state of overpopulation. Both arguments are rejected by clarifying possible definitions of overpopulation.

That policies, which will contribute to a reduction in population sizes or at least counteract present population growth rates, ought to be carried into effect, is a view that is today met with widespread approval. Naturally, the most radical adherents to this position are theorists holding a neo-Malthusian view on population; but also many theorists outside the neo-Malthusian tradition often enunciate the same view. In order to justify whether such policies should be effectuated, one argument is absolutely predominant, namely, that too many people exist. Neo-Malthusians, for instance, often have hard work establishing that there is a problem of overpopulaPlease address correspondence to Jesper Ryberg, Webersgade 19 2100, Denmark. Population and Environment: A Journal of Interdisciplinary Studies Volume 19, Number 5, May 1998 © 1998 Human Sciences Press, Inc.

Copenhagen,

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tion. However, that the question, i.e., whether overpopulation is a genuine problem, is the crucial point when reductions of populations are being considered, is apparently also confirmed by the way overpopulation is traditionally rejected by theorists opposed to the implementation of population policies (as, for instance, theorists in a neo-Marxist tradition). In a recent article on third-world food problems, Kai Nielsen expressed the outlook as typically stated: "The principle problem is not overpopulation . .. but man-made problems, problems on which I will elaborate in a moment when I discuss the Postwar International Food Order"—and he continues—"What we have to recognize is that hunger, malnutrition and famine are fundamental questions of distribution of income and entitlements to food" (Nielsen, 1992, pp. 20, 23). The arguments from both sides of the discussion therefore leave the impression that the question of whether the fact that there is a problem of overpopulation is the primary crux of the matter when different political means are being considered. In this paper I shall discuss whether this is correct. More precisely, I shall focus on what could be called the argument from overpopulation which concerns the relation between the two normative statements: (A) (B)

The Earth, or certain subdivisions of it, is (or will be in the foreseeable future) overpopulated. Policies which reduce the population size (or prevent further growth) of the Earth, or certain subdivisions of it, ought to be carried into effect.

What the argument says is that (A) justifies (B). That the argument from overpopulation is very often advanced in debates is perhaps not strange. It almost sounds truistic that if there exist too many people then we ought to reduce the number of people. Nevertheless, I will argue that the argument is defective. The paper will proceed as follows. First, a traditional approach to the meaning of "overpopulation" will be outlined. It will then be argued that this approach leaves only a weak and politically uninteresting relation between (A) and (B). In the final section an alternative approach to the concept of overpopulation is presented. However, it will once again be argued, though now on different grounds, that there are very good reasons for scepticism with regard to the argument from overpopulation. In more general terms, the conclusion will be that an optimum population theory does not play the role of guide to action in the realm of public policy as is usually assumed.

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OVERPOPULATION Whether there today exist overpopulation problems is a question which, as mentioned, is widely discussed. As part of the annual meeting of the American Association for Advancement of Science, a symposium was held in Boston (1969) on the topic "Is there an optimum level of population?". The answers provided by scientists, representing many different fields of science, showed the coexistence of a broad range of views, including the polar extremes that the world has been overpopulated by far, and, contrarily, that the world is neither overpopulated nor can be expected to be so in the forthcoming future (Singer, 1971). Recent discussions on overpopulation are no less cacophonous. For instance, some strongly enunciate the view that the world population should not exceed one billion people. While others, as indicated by the quotation from Nielsen's article, persistently deny any talk of overpopulation (Shrivastava, 1992). One explanation of this extreme diversity in opinion is probably that it is not often made clear what is meant by "overpopulation." Statements about overpopulation are often presented in close connection to figures or graphs which indicate the growth of a certain population. What these graphs tell is normally the story of exponential growth, of a population doubling time which has fallen rapidly, or a population increase which, in factual figures, has never been higher than it is today. However, such informations does not obviously provide an answer to a question on overpopulation. "Overpopulation" is a normative concept which denotes that a certain area contains more people than it ought to. That a population is too large cannot therefore be deduced from any statistical data about population size, growth or density. That an area is overpopulated (or underpopulated) only makes sense in relation to standards as to how many people the area ought to contain. What is, in more technical terms known as positive and negative maladjustment, presupposes that concept of an optimum size of population. (If A and O respectively denotes the actual population and the optimum population then the maladjustment M = (A-O)/O. Positive maladjustment therefore indicates overpopulation while negative maladjustment indicates underpopulation.) The idea of an optimum population is this: with regard to the moral values which we think should be promoted, there is/are one (or some) population size(s) which is/are, under a set of circumstances, preferable. In order to provide a complete definition of an optimum population it is therefore necessary to specify: (a) the value which should be maximized; (b) the maximization devise which should be employed; (c) the circum-

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stances under which the optimum population size should be calculated. Not all parts of the definition are equally important with regard to the question on the relation between (A) and (B), and need not therefore, be discussed in detail; however, I shall shortly outline what seems to me a plausible account of what could be called the factual optimum population. (a) The definition obviously has to indicate the value which is maximized when the optimum size of population is reached. There is, of course, a logical restraint upon what can function as a plausible candidate for this value, namely, that the value is functional on population size. This restraint has, nevertheless, left room for a very large number of suggestions. For instance, theorists have nominated: the gross national product, military power, ecological integrity, longevity of a population, employment, social harmony, population size (which means that optimum and maximum population coincide), per capita consumption, eugenic selection, real wages per capita (Wogaman, 1973; Potter, 1973). The multitude of suggestions sometimes leave the impression that the choice of value is totally capricious. Surely, this is implausible. In fact it is hard to believe that all suggestions are meant as rival nominees. That a policy which would bring demographic effects most favourable to the advancement of employment or military power should be the preferable one, is obviously implausible. Realizing that each of the suggested values provide an unacceptable narrow concept of an optimum population, some have alternatively suggested a synthetic optimum or an intergral optimum which seek to harmonize some of these values in one definition (Wogaman, 1973). These definitions face the problem of explaining consistently why some values are selected while other are excluded. It seems that a definition of the optimum population should involve a more basic value. In principle this may still leave several nominees. A plausible suggestion, often adhered to, would be to say that the optimum population maximizes well-being. In order to make such a suggestion operational it will, of course, require clarification of what exactly is meant by well-being (or any alternative values that might be suggested). In the present context it is, however, not important to elaborate on this question. (b) The contribution by moral philosophers to the discussion within the optimum population theory has mainly consisted in considerations on what sort of maximization devise is the most plausible. Which of two states of affairs is the more desirable has traditionally been determined in either of two ways. The total view holds that the desirability of a state of affairs is determined by the total sum of well-being. The average view determines the desirability of a state of affairs by the average amount of well-being. The most plausible seems to be the total view. The average view covers

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several interpretations differing in the number of people incalculated in order to compute the average; each interpretation faces serious problems. For instance, the average view implies that the existence of one or a few persons with lives at a very high level of well-being is preferable to a very large population also at a very high, though marginally lower, average of well-being. Or conversely, that a large population of suffering people is preferable to a single person who suffers marginally a little more than each person in the population. Since these kinds of counter-arguments to the average view have been throughly discussed elsewhere I will leave references in a footnote, and merely assume that the total view provides the most plausible way to maximize (Broom, 1992; Sikora, 1975; Bayles, 1980; Scott, 1978). However, there is something else, often ignored in discussions on optimum population theory, which it is important to underline. The optimum population of an area is determined at a certain time, say t,. The definition, however, would be highly implausible if it claimed that the optimum population is the population size which maximizes well-being at t,. This would imply that a population might be of optimum size at t1, even though this would result in a catastrophe in terms of well-being for all subsequent generations. Surely this is morally unacceptable. Thus, a plausible account is not one which maximizes well-being at t1, but one which incalculates the well-being of future generations by maximizing over time. (c) The part of the definition which is, in the present context, the important one concerns the clarification of the circumstances under which the optimum population is calculated. One interpretation of the optimum population, which I think is the most common, is that it indicates the population size which is preferable with regard to the physical and social settings of the target area. For instance, if we ask whether Nigeria is overpopulated what we mean is whether the actual population of Nigeria exceeds the population size which would be preferable when all other things, which have an impact on well-being, are as they are in this country. This concept of an optimum population, which I will call the factual optimum population because it indicates the preferable population size under the actual conditions of an area, could then be defined more formally in the following way. Suppose W denotes the total of well-being—P is the population size—and x,,x2,x3, xn are the conditions which have impact on people's well-being. The total of well-being will then be a function of the population size under a set of circumstances, that is W = f(P, X1,x2,x3, xn). P can now be said to have reached the optimum when the conditions X1,x2,x3, xn are constant, and indicates the actual state of affairs, and neither an increase nor a decrease in P can augment W.

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In order to determine the optimum population of an area it is necessary to clarify which conditions have an impact on W; not only does this include the conditions at ti but also the future conditions since the optimum maximizes well-being over time. Obviously this set of conditions is extremely large. Consider the following examples: Technological capability: The present and future technological capability obviously has much influence on human well-being. Inventions of new technologies may make it possible to substitute for, what is at one time, a scarce resource with other less scarce resources. Agricultural improvements may increase food production. Shortage in energy resources may be surmounted by technological progress. For instance, Alvin M. Weinberg and Philip R. Hammond argued at the Boston Symposium that with the advent of fusion reactors, there will be an inexhaustible source of energy which can almost freely be converted into other kinds of resources (Weinberg & Hammond 1971). New technologies may, on the other hand, also lead to an increase in pollution or create serious waste disposal problems. Examples of how technology affects human well-being are, of course, numerous. Population distribution: Another thing which has an impact on wellbeing is the spatial distribution of a population. People may be affected by a feeling of being too close to each other. Moreover, a large concentration of people in large urban agglomerations may make it more difficult to conduct an area effectively. One spatial distribution pattern may also facilitate the access to vital resources compared to other patterns of distribution. Resource distribution: The way resources are distributed within a population obviously has significant impact on the sum of well-being. This is the case both with regard to distribution of resources between members of the same generation and resource distribution across generations. These three examples are, of course, only a small part of the circumstances which have an impact on well-being and which should therefore be included among the ceteris par/bus conditions when the optimum population is determined. A complete list would be very comprehensive. On the grounds of the previous considerations we can now present a possible definition of the factual optimum population. The optimum population of an area at t1, is the population size which, under the actual state of affairs at t1, maximizes well-being over time. As mentioned, there has been a tendency in alternative definitions of the factual optimum population to suggest that the optimum should promote some less fundamental values while ignoring other aspects of what matters with regard to human life, or to ignore the view that the optimum should incalculate effects on the lives of future generations. Both aspects are included in the present

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definition, and I will here assume that if one defends a factual approach to the optimum population then this definition provides the most plausible account. As an implication of this definition we can define population maladjustment as well, by saying that an area is overpopulated (or underpopulated) if there is a mismatch between the actual state of affairs of the area and the population size, with regard to the promotion of well-being. THE ARGUMENT FROM OVERPOPULATION Some population theorists have suggested that there is a tendency in human populations to move toward their optimum size. The argument is that human procreation and death will adapt to the physical and social circumstances. Over- and underpopulation will therefore be adjusted by some sort of natural feedback mechanism. However, on the ground of the suggested definition of the optimum population it is hard to believe that an invisible hand will resolve the problem of a discrepansy between the actual and optimum population. Even if it is correct that the actual population size of an area tends to find some kind of balance with the existing physical and social environment there is no need to believe that this balance is the most appropriate in terms of future well-being. A single example is sufficient to illustrate this point. A finite resource may set an upper natural limit as to how many people can, at a certain time, be sustained. But surely this limite need not be the most appropriate over the long term. If the resource is slowly renewable it may be exhausted by the population size it is able to sustain at t1. A balance between population size and the environment may thereby have severe implications for future generations. Thus, there is no reason to think that political means will not often be required in order to bring the actual population of an area and the optimum population into adjustment. This is basically what the argument from overpopulation is all about. According to the argument (A) implies (B). That is, there exist, either globally or locally, problems of overpopulation; what ought to be done, therefore, is to effectuate policies which will reduce population size. Despite the prima facie plausibility, I think it faces two problems which are much too often ignored. The first problem concerns transition between different states of affairs. The optimum population indicates the preferable population size under a set of conditions; however, there may be difficulties in realizing this population size. If, for instance, it is estimated that the actual population is twice the optimum population size then one cannot just halve the existing number of people. As an extreme example it would surely have terrible effects

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in respect of well-being if one decided to exterminate half the population. A policy which intended to lower population size would, of course, normally try to influence fertility rates not death rates, but such a policy may well have serious consequences. Some neo-Malthusians, who have most strongly emphasized the existence of overpopulation problems, have as a cure suggested coersive population policy programmes involving for instance compulsory abortions or vasectomies. Such policies obviously would have dramatic impact on people's lives. But this means that (A) does at least not necessarily justify (B). It is necessary to make sure that what is gained in terms of well-being by realizing the state of optimum population is not outweighed by what is lost by the policy which brings the optimum and the actual population into adjustment. The second, and more serious, objection to the argument from overpopulation concerns the variability of the optimum population. The optimum population, as defined above, is determined relative to a set of ceteris par/bus conditions. However, a change in any of these conditions may obviously entail that the optimum population is changed radically. Historically, it is, for instance, reasonable to assume that the optimum populations of certain European countries have increased considerably. That the optimum population is, in this sense, dynamic has some serious practical and even more serious logical implications. The practical problem has to do with the fact that to bring the actual population into accordance with the optimum size is often not something that can (or should) be done immediately. Even if a population policy which reduces fertility rates significantly is effectuated it may take a very long time to reach the optimum size, for instance, because of the population momentum (the phenomenon that a youthful age-structure of a population may result in population growth for decades even if fertility has reached the replacement level) (World Bank Publication, 1994, pp. 2528). But this means that when the population size, which was first regarded as the goal, has finally been reached, the optimum population may have changed significantly in the meanwhile. Thus, the variability of the optimum population creates an obviously practical problem with respect to applying the optimum as a goal in the realm of policy. In fact there is an even more serious snag about this problem. As a result of the interrelatedness of demographic, economic, ecological, social, psychological, and cultural factors, population policies often have non-demographic side-effects. But this means that a change in population size, caused by a policy which seeks to realize the optimum population, may affect the ceteris paribus conditions and thereby change the optimum size itself. Surely this is a problem that should be accounted for when population policies are recom-

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mended, and which also indicates that mere reference to (A) is not sufficient to justify (B). That the optimum population is dynamic has another purely logical implication which is even more important with regard to the relation between (A) and (B). Suppose that the population of a certain area exceeds the factual optimum population, i.e. the area is overpopulated, and that there will be no transition problem, in the sense that the loss in well-being by changing the actual population is nothing compared to what will be gained when the optimum size has been reached; will the argument from overpopulation then be sound? On the ground of the previous considerations it is clear that the answer must be in the negative. Consider again the function W=f(P, X 1 ,x 2, x 3, xn). If the value of P which augments W is exceeded by the actual population size of the area then we might reduce the population, but we may as well change some of the conditions X1,x2, x3, xn on which W is functional. To put it another way, if the area contains too many people we might reduce that actual population, but we may as well try to raise the optimum population. That we ought to avoid overpopulation justifies both procedures. Reference to the fact that an area is overpopulated is in that sense much more politically uninteresting than is often assumed. It may provide a part of a justification of the traditional neo-Malthusian recommendations of population policies, but it may as well be part of a justification of the neo-Marxist suggestions about redistribution of resources or restructuring in the socio-economic system. (Naturally, an area might be overpopulated even if resouces were redistributed or other cognate policies were carried into effect. It would then, as I shall return to in the final section, seem more reasonable to conclude that the population policies should be effectuated. However, this is surely a much stronger claim to make than to claim that (A) implies (B).) The mistake in the argument from overpopulation simply is to ignore that the total of well-being is not only functional on population size but also on the circumstances under which people lead their lives. It is worth noticing that the same mistake is sometimes made by neoMarxists and Cornucopians. According to an often presented argument— let us call it the argument against overpopulation—many of the present problems can be solved by other political means than population policies and it is therefore concluded that nothing like overpopulation is at stake. Just like the argument from overpopulation, the argument seems prima facie quite plausible; for instance, it sounds reasonable to claim that if famine and other problems which have a severe impact on people's wellbeing could be overcome by redistribution of the existing resources then the problem is not that there are too many people. On the ground of this

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kind of reasoning some even talk about "the myth of overpopulation" (Hartmann, 1987). However, nothing of the kind is implied if we employ a factual concept of an optimum population. That an area would not be overpopulated if another pattern of resource distribution were adopted does not show that the area is not overpopulated under the existing set of conditions. Thus, the argument against overpopulation is also unsound. The conclusion of this section is simple. If we rely on a factual interpretation of an optimum population, which indicates, in terms of wellbeing, how a population size matches the actual circumstances of an area, then (A) does not justify (B). The inference ignores the fact that the transition from the actual population size to the optimum population might in itself involve greater losses in well-being than that which would be gained if the optimum population was realized. But, most important, it ignores the fact that overpopulation may, from a logical point of view, be equally well overcome by changing the circumstance to fit the actual population as by changing the population size in accordance with the actual circumstances. Which strategy is preferable depends upon further ethical considerations. Thus, the argument from overpopulation is unsound and consequently does not resolve the disagreement, with regard to political means, between antagonist parts in the population debate.

OVERPOPULATION REINTERPRETED There is an obvious objection which can be raised against the conclusions in section two. The argument from overpopulation does not, or at least so it could be responded to, ignore the implications of the meaning of "optimum population," rather it relies on a different definition. The definition presented in the first section is only one among many which have been suggested (at the Boston Symposium alone three different definitions were presented) (Singer, 1971, p. XI, p. 9, p. 224). The crucial part of the factual interpretation of the optimum population is that the optimum population is determined relative to the actual circumstances of the target area. This means that the optimum is variable due to changes in circumstances. This factual aspect to the optimum population might be rejected and my claim, that the argument from (and against) overpopulation is not sound, might then be reinterpreted simply as a matter of definitely disagreement. The question, therefore, is what is required by a definition which makes the argument sound. A possibility, which provides a hint of what this definition would be, has been suggested by theorists mainly holding an ecological approach to

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population questions; that is, to identify the optimum population with what is sometimes called the "population ceiling" or the "carrying capacity." The idea behind these concepts is that the Earth (or parts of it) contains only a finite amount of resources and that consequently there is an upper limit to the number of people it is capable of sustaining. The limit indicates the optimum population. This suggestion is captured in the following definition by Ehrlich: What must be done is to determine how much "good" should be available for each person. Then just how many people can enjoy that much "good" on a permanent basis can be determined, at least in theory. The number of people would then be one "optimum" population size for our finite planet (Ehrlich & Harriman, 1971, p. 12). The idea, as it is also expounded by others, is that it should be decided what is a reasonable average unit of resource consumption per person. The total of the global resources divided by the average consumption of resources thus represents the optimum population of the Earth. In reality, things are of course more complicated than they appear from this calculation. For instance, not all natural resouces exist in finite amounts. Some resources are renewable if not exhausted. This complexity is probably meant to be captured in Ehrlich's definition by the phrase "on a permanent basis." Thus, the optimum population is the maximum number of people that the Earth, or a piece of land, is able to sustain over the long term. Ehrlich's definition is not plausible. It suffers from the flaw that it only focuses on one aspect of what is important with respect to the quality of a human life, e.g., resources. If a piece of land contains very large numbers of resources, it is hardly reasonable to claim that the preferable population size would be the number of people that could be sustained if this, for instance, entailed a population density which would make it impossible to conduct the area effectively, and which would cause social stress or result in enormous waste disposal problems. Moreover, the definition employs an oversimplified concept of resources ignoring the importance of technology. Technologies are not static. Even if the physical world is unchanged, the utilization of resources will change when technologies progress. What counts as a natural resource is per se partly determined by which technologies are available at a certain time. The dependance of resources on technology, therefore, makes it difficult to ascribe a clear meaning to the concept of "a total amount of resources" which is supposed to function as the numerator when the optimum is calculated. Despite these serious flaws

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Ehrlich's definition does, nevertheless, provide an indication of the alternative interpretation of an optimum population which might be suggested. Suppose that it is established that a certain piece of land is overpopulated and that "overpopulation" refers to an excess of the optimum population as defined by Ehrlich. It can then no longer be claimed that the optimum population of the area can simply be raised by redistributing available resources, because the definition already presupposes what may well be assumed to be the optimal distribution of resources, namely, an equal distribution. If the total amount of resources is devided by the resources needed per person and if this optimum population is exceeded, it will apparently no longer be a plausible objection that, rather than reducing the population size, we should instead distribute the resources differently to raise the optimum. This indicates an alternative interpretation of the optimum population. Rather than determining the optimum relative to the actual circumstances of an area it could be determined relative to the circumstances when they are as good as they possibly can be. This may be, for instance, when all (affectable) circumstances are such that they form the best possible background for maximizing well-being. Formally put, we can then say that if W=f(P,x1,X2,x3, xn) then P will be of optimum size when X1,X2,x3, xn are optimized and neither an increase nor a decrease in P can augment W. (Due to the interrelatedness between the different affectable conditions this does not necessarily mean that each condition is individually optimized; the crucial point is that together they form the best possible background for promoting well-being.) Of course, one does not have to claim that the best state of affairs is the one in which all conditions are optimized with regard to maximizing well-being. An equalitarian might, for instance, claim the best distribution pattern is one which divide resources equally rather than the one which maximizes well-being. But it seems that a plausible definition would, nevertheless, be one in which at least some conditions maximize well-being. The important thing is that the optimum indicates the best possible state of affairs both with regard to population size and circumstances. Let us call this the ideal definition of the optimum population. Apparently, some employ an ideal concept of an optimum population. For instance, Friedrich Engels has critized Malthus' population theory in the following manner: But it is ridiculous to speak of overpopulation while "the valley of Missisippi alone contains enough waste land to accommodate the whole population of Europe," while altogether only one-third of the earth can be described as cultivated, and while

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the productivity of this third could be increased sixfold and more merely by applying improvements which are already known (qouted in Meek, 1971, p. 63). This clearly indicates that Engels does not rely on a factual optimum population but some kind of ideal definition. In general, what I called the argument against overpopulation seems much more plausible if based on an ideal optimum population. But how does the ideal interpretation affect the argument from overpopulation? With regard to the objection that the argument from overpopulation ignores that the transition from a state of overpopulation to a state in which the optimum population is realized may involve losses in well-being, it is still a logical problem to the argument but perhaps less likely to be true. If the population of an area exceeds the ideal optimum population and the actual circumstances within the area are not even optimized (which is probably in reality always the case), then it is reasonable to expect that there is a very large lack of balance between the population size and the actual circumstances of the area and that the benefit of reducing population size therefore is likely to outweigh the losses. Though the objection still holds one might claim, therefore, that it is further weakened if one employs an ideal rather than the factual interpretation of the optimum population. With respect to the main objection to the argument from overpopulation, namely, that we might as well raise the optimum population by changing the circumstances instead of reducing population size to fit the actual circumstances, this is no longer sound. If an area is overpopulated then we cannot bring that actual and the optimum population into adjustment by political means such as redistribution of resources, land reforms, or any other changes in the socioeconomic system, because the ideal optimum population already presupposes that these conditions are optimized. No change in the ceteris par/bus conditions will therefore raise the optimum population, thus it seems that if (A) is correct then it now actually justifies (B). So, with regard to both objections it might be claimed that they are not reasonable because they ignore the fact that those who pose the argument from overpopulation in the population debate simply do not rely on the factual but on an ideal conception of the optimum population. A well-known structure when criticizing arguments is to show that the arguments are not valid or, alternatively, that if they are by some kind of evasion made valid, they will have to rely on a least one premise which is false. The interesting question is whether this is also the situation in the

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present case. If those who posed the argument from overpopulation rely on the ideal population optimum then it surely seems more reasonable that (A) justifies (B); however, now the question rises whether (A) is at all true. That there is a mismatch, in terms of well-being, between the actual physical and social environment and the population size, in parts of the world today, is probably correct—but if we ask whether these areas exceed the ideal optimum this seems much less likely. Suppose that we once again ask whether Nigeria is overpopulated, what we then have to consider is whether the population of Nigeria exceeds the population size that would be preferable if everything, such as the economical, social, environmental, technological conditions, were as good as they possibly could be. Surely this would be to depict a scenario of Nigeria totally different from the Nigeria we know. Probably, there are no countries in the world today, not even the richest ones (which have a much higher population density than Nigeria), in which the physical and social conditions could not be improved; thus, the question is whether it might not be the case that the actual population of Nigeria falls below the population size that could be carried if all affectable conditions were optimized. That is, whether Nigeria in ideal terms should be characterized as underpopulated? Of course, it is necessary to clarify what exactly the conditions are "as good as they can possibly be" means, but in any plausible interpretation of "possibly" the Nigeria scenario that will be depicted will surely be much different from the present Nigeria. As I have already indicated, it is very difficult to compute the optimum population of an area. In practice it may even be impossible. Thus, there are good reasons to be very careful with statements on whether or not a certain area is in fact overpopulated. The conclusion I will draw in this section is therefore a more modest one, namely, that one might rely on an interpretation of the optimum population, which makes it more reasonable to claim that (A) justifies (B), but one should then be well aware that in order for (A) to be true one will have to establish that the actual population of the target area exceeds what would be the preferable population size if all conditions within the area were optimized. Surely one may wonder whether any who claim that there are today problems of overpopulation, have really provided this kind of evidence (see Graham & Graham, 1992). CONCLUSION As indicated in the previous sections, discussions concerning questions about overpopulation do, in my view, suffer from serious confusions.

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The first problem that affects the clarity of the discussions is, as mentioned, that most population debaters either make statements about overpopulation without any definition of what counts as the optimum population, or on the ground of definitions which are totally arbitrary. What I have pointed at, however, are the more profound confusions relating to the claim that there are present problems of overpopulation and that this fact clarifies which political means should be adopted, e.g., policies that influence the demographic situation. Many apparently advocated variations of the factual interpretation of an optimum population. In this case, however, policies which for instance cause changes in the socioeconomic system— as traditionally recommeded by neo-Marxists—may as well function as instruments to cope with overpopulation as policies which regulate population size. Thus, stronger arguments are required in order to justify that the latter category of policies is preferable to the former. Alternatively, one might employ an ideal concept of optimum population. However, if that is the case it is important to be aware whether it has in fact been established, or at least made probable, that there are problems of overpopulation. Surely this is a heavy burden of proof. Another way to put this is to say that parts of the population debate suffer from a misunderstanding of the way optimum population theory function as a guide to action in the realm of public policy. The mistake is to believe that the optimum population indicates the population size that ought to be realized in the sense that it is justified to change the actual population size if it does not harmonize the optimum. If one relies on a factual optimum the assumption is mistaken because the right action might be to make the optimum size match the actual size by changes in conditions. If one relies on an ideal optimum the assumption is obviously mistaken—it may have catastrophic consequences to realize the optimum size under sub-optimal conditions (think of the Nigeria example). The conclusion of the paper is that the argument from overpopulation is not valid, or at least that there are very good reasons to be sceptical when the argument is posed. As a general and more modest conclusion, the previous considerations indicates that the concept of overpopulation, and its political implications, should be handled carefully—more carefully than is often the case in population debates.

REFERENCES Attfield, R. & Wilkins, B. (eds.) (1992). International justice and the third world. London: Routledge.

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