Human Cultural Evolution: The Malthusian Theory
by Lynden S. Williams
This is the first of three papers that examine the ‘supply-side’ theory of human cultural evolution and the alternative ‘demand-side’ theory. The ‘supply-side’ theory was expounded by Thomas Malthus in the early 1800’s as The Principle of Population, and in 1830 in a shortened version as A Summary View of the Principle of Population, referred to generally as the Malthusian Theory. The ‘demand-side’ theory was laid out by Ester Boserup in her book The Conditions of Agricultural Growth: The Economics of Agrarian Change under Population Pressure, published in 1965. We will begin with an examination of the ‘supply-side’ (or Malthusian) theory, and turn to the ‘demand-side’ (or Boserup) theory in the next paper. The third paper will examine human cultural evolution and argue the Boserup Theory is the better explanation of how and why those evolutionary processes occurred, and explore some of the implications.
Many persons with interest in this topic will be tempted to assume they need not read this first section on the Malthusian Theory; we have known about that theory since high school, and have no need to review it. I suggest that text book explanations of the Malthusian Theory usually emphasize the two postulates Malthus employed to support his view and often fail to even acknowledge the logical deduction that constitutes the core of this theory. Most historians would reject the Malthusian Theory, but when one reads their work it is often apparent that Theory is prominent in their thinking (see reference to V. Gordon Childe below). In order to understand the Boserup Theory, we must have a clear understanding of the alternative Malthusian Theory.
I am strongly biased against the Malthusian Theory, but I cannot disprove that Theory. I can show that the postulates he used to support his theory have been incorrect over the past 200 years since he espoused them. But that does not preclude the possibility that the theory may be correct for reasons that he did not state, or correct in some places or at some times in the past; and it certainly does not preclude the possibility that it can hold true in the future. I am strongly biased in favor of the Boserup Theory, but I cannot prove it is correct. I can demonstrate how and why the Boserup Theory could explain much of human cultural evolution and why that explanation is far more persuasive. But that does not preclude the possibility that the alternative perspective could have produced the same result, nor can I know with any degree of certainty whether the Boserup Theory will be relevant to the future of humans.
What caused early humanoids to become omnivorous (the change from vegetarian to a diet that includes meat)? Was that change predictable? Can we know what sorts of individuals or groups first made that change? What caused early people to leave their homeland in the hot wet tropics of Africa and take up residence in the seasonally dry tropical savannas? What caused them to migrate into the seasonally cold latitudes of Europe? Was their motive the same as for those who had previously migrated to the savannas? Did that same motive cause some groups to become farmers, and later, to develop the urban-industrial society? If so, we may be able to identify the ‘prime driver’ in human cultural evolution, and have a real basis for explaining how and why the transformation of humans from hunter-gatherers in the hot wet tropics to urban-industrial societies, covering most of the ice-free land surface of the earth, occurred. And, if there is one more stage in human cultural evolution, we may have some basis for speculating which societies will make that transition.
Each stage in human cultural evolution was coincident with a rapid expansion of the population and therefore must have also been coincident with a significant expansion in the production of food. Obviously these two variables must increase (or decline) in tandem; the human population could not increase without an increase in the supply of food, and people would not gather or produce food and other goods unless there was demand. But which is the basic cause and which is an effect? If an increase in food production causes or allows people to increase their population then the ‘prime drivers’ of human cultural evolution must have been those individuals and societies that discovered or learned how to increase the food supply. If an increase in population causes people to increase their supply of food, then we need to focus on why population pressure occurred in one region or among one group, rather than some other region or group.
For most of human history ‘supply’ consists primarily of basic food, and changes in ‘demand’ resulted from population growth or decline. The supply-side theory holds that increased or decreased production is the cause for changes in demand—that is, population growth or decline. The demand-side theory holds that an increase in demand resulting from population growth is usually necessary to stimulate those innovations and changed methods that would cause supply to increase. Obviously, basic food is a small, albeit essential, component of demand in most countries today, and it constitutes an equally small share of the total supply of goods and services. However, whether supply and demand is made up mostly of basic food or a combination of food and other goods and services, the question remains: Is it increased supply of goods and services that causes demand to increase, or is it increased demand for those goods and services that caused the supply to increase? It is argued here that the ‘supply-side’, or Malthusian Theory, and ‘demand-side’, or Boserup Theory, are equally relevant today as in the past when the primary issue related to food production and population growth.
The Malthusian and Boserup Theories imply human histories that are so contradictory and so divergent in their cause and effect interpretations, that the two stories can scarcely be recognized as dealing with the same species on the same planet. Without a clear understanding of both theories, one cannot have a valid basis for judging the validity of historical arguments presented. Any serious student of human cultural evolution must be able to recognize the perspective of the speaker with regard to the cause and effect relationship between increased productivity and growth in demand. Providing that basis for recognizing that perspective and ability to contrast that perspective with the alternative view, is the purpose of this, and the following papers.
Ladder of Civilization
In the Old Stone Age men relied for a living entirely on hunting, fishing, and gathering wild berries, roots, slugs, and shellfish. Their numbers were restricted by the provision of food made for them by Nature...In Neolithic times men control their own food supply by cultivating plants and breeding animals...so that... a community can now produce more food than it needs to consume, and can increase production to meet the requirement of an expanding population. ...To secure bronze tools a community must produce a surplus of foodstuffs to support bodies of specialist miners, smelters, and smiths withdrawn from direct food production. V. Gordon Childe.
Clearly Childe subscribed to the ‘supply-side’ or Malthusian Theory of human cultural evolution. That is, he assumed that the plant-animal symbiosis we call agriculture resulted from discovery or innovation by humans in a deliberate effort to increase production in order to provide for a growing population. Many plants and animals evolved a mutually beneficial symbiosis with one or more other life forms. That evolutionary process is well known to biologists and known to occur over a period of thousands of years. Humans, in contrast to other life forms, can become aware of this process and greatly speed and refine it. But do we suppose humans achieved it as a discovery or innovation? Don’t we know animals tend to scatter seeds of the plants they consume? Don’t we know that some of those plants become dependent upon the animal to scatter their seeds, and gradually lose the ability to fly on the wind or whatever method they used previously to get themselves planted? Do we suppose humans were not molded by the same evolutionary processes that designed other forms of life? And incidentally, why would early humans have produced more food than they needed? Did they anticipate an urban market where they could exchange their surplus food for manufactured products?
Similarly, the movie Space Odyssey 2001 included an introductory segment meant to illustrate the evolution of man as a tool maker and tool user. The scene was set in a tropical grassland region during the dry season as two clans of pre-humans compete for a water hole. The clan with the largest and strongest male wins that competition and the clan of the weaker male is forced to retreat. Later a male member of the weaker clan absent-mindedly picks up a short tree limb and in frustration slaps it at a nearby skull; he notices that the skull is smashed. He hits at another skull and gets the same result; one can see and feel the jubilation and exhilaration of the ‘inventor or discoverer’ of the club. The next day at the water hole the tide turns against the big strong male and in favor of our inventive hero. [Obviously, no historian would have bought into that story. Pre-humans could never have competed on the savannas without weapons that would bring down the large grassland animals and allow them to defend themselves against the large predators. And, the issue of why pre-humans, who did not use the club, had an opposable thumb with which to hold it, was not addressed.]
These two examples are typical of how human cultural evolution is generally portrayed—that is, as a struggle up from brute savagery to civilization, in which each rung in that ladder was achieved by innovation or discovery. Indeed, the focus of history is often on the timing of those advances and the individual or group that achieved the break through that allowed humans to move to a higher level of civilization and presumably higher level of well-being. Thus, the discoverers or innovators who are able to bring a more productive technology or land use system into existence are often considered the prime drivers in human cultural evolution. In that sense, history is a celebration of those individuals and groups who made it possible for humanity to escape the forests of Africa and settle the savannas and later settle the seasonally cold latitudes, to become food producers rather than hunter-gatherers of wild plants and animals, and to achieve the urban-industrial lifestyle. Certainly Thomas Malthus subscribed to that theory of human cultural evolution.
The “Malthusian Theory” demonstrated how and why human population growth would lead necessarily to impoverishment or indeed starvation, unless new methods and technology were sufficient to offset diminishing marginal returns to labor. He was well aware that in the past (prior to 1800) improved methods of food production were sufficient to provide for a growing population. He did not, however, believe innovation could provide for a growing population in the future. Discussion of the Malthusian Theory is often confined to the issue of whether introduction of improved methods and technology can continue to provide for a growing population and higher levels of well-being in the future, rather than whether or not that theory, and the human cultural evolution it implies, is correct.
The central tenants of the Malthusian Theory, the tendency for populations to increase through time and the Law of Diminishing Returns to Labor, greatly precede Thomas Malthus. Likewise, the view of human cultural evolution as a struggle up the ladder of civilization with innovation and discovery being the cause for that progress, has probably been taken as ‘common knowledge’ from the beginning of human speculation about the how and why of our history. Malthus is credited with organizing those ideas into a comprehensive theory of cultural evolution.
History is often presented as a Malthusian interpretation of the relationship between innovation and population (or production) growth. Environmentalists and futurists of other stripes may disavow that Theory. However, their predictions and projections of the human future are often largely predicated on the Malthusian interpretation of human cultural evolution. If we are to understand human cultural evolution and projections of that past into the future, we need to have a clear understanding of the fundamental ideas those projections are based upon. And, we need to understand as well that there is an alternative theory which produces a radically different interpretation of how and why humans have come to be as we are, and what changes are to be expected in the future.
The Malthusian Theory
THE IRON LAW OF WAGES: “In the natural advance of society, the wages of labor will have a tendency to fall, as far as they are regulated by supply and demand; for the supply of labor will continue to increase at the same rate, while the demand for them will increase at a slower rate.” David Ricardo.
The Iron Law of Wages was first stated by Ferdinand Lassalle, although the theory behind it was formulated earlier by Thomas Malthus. The essence of the Iron Law of Wages is that anything that would cause wages to rise above the minimum subsistence level would set into motion forces (namely an increase in labor produced by population growth) that would necessarily bring wages back to the subsistence level. In short, only absence of food could prevent population growth to, or somewhat beyond, the capacity of potential production.
Malthus stated: “...we cannot fail to be struck with a prodigious power of increase in plants and animals” (p. 44). Using the example of wheat, he noted that a single acre of wheat can easily yield sufficient seed to plant six acres the next season, and those six acres could yield seed for thirty-six acres in the following season; at that rate of increase the entire surface of the earth could be covered with wheat in just fourteen years [614 = 78 billion acres; compared to about 37 billion acres of land on earth]. Likewise, he noted that sheep are able to double their numbers every two years; if we begin with the number of sheep that can be sustained on one acre of pasture and double that number every two years, the entire land surface of the earth would be filled to capacity with sheep in just seventy-six years. Malthus observed that the land surface of the earth could not be covered with wheat or sheep because: (among other reasons) ...“it would be impossible for the most enlightened human efforts to make all the soil of the earth equal in fertility to the average quality of land now in use” (p. 45). With regard to plants and non-human animals Malthus concluded: “...notwithstanding this prodigious power of increase in vegetables and animals, their actual increase is extremely slow”; because the resource base upon which they depend cannot be increased at that rate. In the case of non-human life, he noted that the resource base was mostly fixed, except to the extent that humans can modify that resource base, say for cultigens and domestic animals.
Applying this principle of population to human population growth, Malthus noted that: “It may be safely asserted, therefore, that population, when unchecked, increases in a geometrical progression of such a nature as to double itself every twenty-five years” (p. 52). He based that assumption on the doubling of the U.S. population between 1795 and 1820 which he ascribed to the abundance of good land resources available to the population (there was very little immigration into the U.S. between 1795 and 1820). He assumed that all human populations would double every 25 years if they also had ample productive resources available to them. A 25-year doubling period implies a geometric rate of three percent annually, so that it would take several hundred years to reach the astronomical numbers that wheat could achieve in fourteen years and sheep in seventy-six years. For example, if 1,000 people maintained a growth rate of 3 percent annually, in 600 years they would number 50 billion [1,000 X (1.03^600) = about 50 billion). Notwithstanding the greater amount of time required, the term ‘prodigious’ is certainly not an improper characterization of the potential for human population growth. Malthus noted that: “If his natural capacity of increase be greater than can be permanently supplied with food from a limited territory, his increase must be constantly retarded by the difficulty of procuring the means of subsistence” (p. 45).
Malthus knew people could increase production by working their land more intensively. That is, people can space plants closer, cultivate more often, cover plants with glass to prevent freezing, apply more fertilizer, water plants more carefully, etc. However, he noted that in the absence of an increase in farm land, increased food production would require “the gradual and laborious improvement of the land already cultivated… (and that) the yearly increment of food would …have a tendency to diminish, and the amount of the increase of each successive ten years would probably be less than of the preceding” (p. 52). The economic law of diminishing returns to labor assures that additional units of labor applied to a constant amount of land, will (absent a change in methods) result in a reduction in the marginal (and thus average) return to labor. Malthus continued: “By the laws of nature man cannot live without food. Whatever may be the rate at which population would increase if unchecked, it never can actually increase in any country beyond the food necessary to support it” (p. 54). He stated: “Elevated as man is above all other animals by his intellectual faculties, it is not to be supposed that the physical laws to which he is subjected should be essentially different from those which are observed to prevail in other parts of animated nature. ...suppose that by great attention to agriculture, its produce could be permanently increased every twenty-five years by a quantity equal to that which it at present produces...a rate decidedly beyond any probability of realization (emphasis mine). The most sanguine cultivators could hardly expect that in the course of the next two hundred years each farm in this country on an average would produce eight times as much as it produces at present, and still less that this rate of increase could continue so that each farm would produce twenty times as much as at present in five hundred years, and forty times as much in one thousand years. Yet this would be an arithmetical progression and would fall short, beyond all comparison, of the natural increase of population in a geometrical progression” (p. 53).
Malthus also knew that diminishing returns to labor could be offset by innovation and new technology. He stated: “while improvements in agriculture ... might for some time occasion a rapid increase of food and population ... These variations, however, obviously arise from causes which do not impeach the general tendency of a continued increase of produce in a limited territory to diminish the power of its increase in (the) future” (p. 52). Furthermore, he believed the law of diminishing returns applied to innovation, as well as to labor, land, and capital. That is, he assumed that an innovation allowing production to increase from say 30 to 40 bushels per acre would be more easily achieved than one that increased production from 40 bushels to 50, and indeed he suggested that the potential for such innovations is very limited, or perhaps absolutely limited; he stated: “..we are indebted wholly to the ignorance and bad government of our ancestors. If they had properly called forth the resources of the soil, it is quite certain that we should not have but scanty means left of further increasing our food” (p. 57). Thus, each innovation that increases production will not only serve to increase the population, but will also limit the potential for new innovation that could further increase production.
The issue raised by Malthus was not whether human population growth would continue or stop. He was certain that it would stop; it would either be stopped by positive checks or it will be stopped by preventive checks. Either people would continue to do what comes naturally and soon find growth stopped by hunger and poverty (positive checks), or we will see that disaster coming and reduce our fertility before we run out of food (preventive checks). Given those two options, Malthus (and all other rational people) preferred the latter. Obviously, Malthus was aware of the fact that humans could limit their growth by birth control, abortion, and infanticide; however, he opposed those methods because he believed they were wrong (vice, as he put it). He therefore recommended postponement of marriage or abstaining from sex as the appropriate “preventive checks” on population growth.
Malthus’ objection to birth control and abortion is not material to his theory, and inclusion of birth control/abortion in that model does not make the “neo-Malthusian model” new. Malthus’ religious beliefs have nothing to do with the validity or lack of validity of his theory. [On the other hand, modern Malthusianists usually emphasize environmental degradation and destruction associated with population growth, rather than (or in addition to) diminishing returns to labor and technology, as the essential limit on increased production; in that sense it is neo-Malthusian.]
Given the dire consequences of population growth, and Malthus’ belief that the “laboring classes” were unlikely to limit their growth by preventive checks, he suggested that attempts to limit the suffering and hunger of the poor (provided at that time by the “poor tax”) would be counterproductive. He hoped that only the most desperate would accept such assistance. He stated: “...if it is so discreditable to receive parochial relief, that great exertions are made to avoid it, and few or none marry with a certain prospect of being obliged to have recourse to it, there is no doubt that those who were really in distress might be adequately assisted with little danger of a constantly increasing proportion of paupers.” If on the other hand, welfare payments are socially acceptable and sufficient to reduce poverty to the point that...”many marry with the almost certain prospect of becoming paupers, and the proportion of their numbers to the whole population is, in consequence, continually increasing, it is certain that the partial good attained must be much more than counterbalanced by the general deterioration in the condition of the great mass of the society and the prospect of its daily growing worse”... then welfare (parochial relief) will do more harm than good (p. 69).
Both Marx and Engels objected vigorously to Malthus’ theory. Marx described Malthus’ essay as schoolboyish, and he accused Malthus of plagiarism and being self-serving. He attributed the jubilant reception of Malthus’ work by the English oligarchy as proof of the work’s attempt to disrupt the efforts by some to improve the lot of humankind. Marx’s work is often cited as an alternative to the Malthusian Theory, even though his objections to the Malthusian Principle of Population was largely confined to a single footnote, and his labor theory of value did not challenge Malthus’ contention that increased production is the cause of population growth, other than suggesting it would be relevant only in capitalist countries. One can certainly view the social implications of the Malthusian Theory as objectionable or even despicable; however, objections based on idealism and morality do not constitute a valid argument against that theory, and certainly do not constitute alternative theory.
The Malthusian Theory is frequently misstated as: Human populations increase geometrically and the food supply increases arithmetically. In fact, Malthus said populations would tend to grow geometrically if food and space were available, but with rare, short term exceptions, food and space will certainly not be available, and therefore human populations will certainly not grow geometrically. He said the arithmetic rate of increase in food production would be the best that could be hoped for, but with rare short term exceptions, an arithmetic rate of increase would be decidedly beyond any probability of realization. An accurate summary of the Malthusian Theory should be stated as his logical deduction (not the postulates he used to support that deduction), namely: That the increase in human populations will be constantly retarded by the difficulty of procuring the means of subsistence, and therefore population growth is dependent upon a prior or simultaneous increase in the food supply.
That passion between the sexes would assure that people would tend to have as many children as they can feed, and that the number of surviving children will depend upon the amount of food they have, was mostly taken by Malthus as too obvious to require much elaboration. He therefore concentrated his efforts on explaining the capacity of humans to increase their population geometrically, and the Law of diminishing returns to labor which would, absent more productive methods, result in lower marginal returns to increased labor, and thus lower average returns for the total population. The concept of diminishing returns to labor is now considered to be a universal economic law so that Malthus’ explanation and defense of that law can be considered redundant. Likewise, it is clear that humans and other living creatures have the biological capacity to increase their numbers geometrically. Therefore, much of the content of Malthus’ work can now be considered to be obviously correct.
On the other hand, diminishing returns to innovation and technology is certainly not accepted today as obviously true. And, the ‘facts’ that people have as many children as they can feed, and that the primary limitation on population growth is the food supply have been false over most of the world during the past two hundred years, and were probably always false. Humans can (obviously do) limit their fertility for reasons that are totally unrelated to their ability or inability to feed additional children. And, the application of innovation and technology can produce (obviously has produced) a rapid rate of growth in production of goods and services, including food.
The Malthusian Theory conforms to the Biological Law of Zero Population Growth. Whereas any form of living creature is biologically capable of increasing at a geometric rate through time, it will certainly not do so over the long term. Said another way, the long-term rate of growth of any species has always been, and must always remain, zero percent. The biological law of zero population growth must be qualified as follows: First, for some species, the population may vary radically from decade to decade (from year to year in the cases of species such as insects and birds) because of short-term environmental factors, even though the long-term average remains relatively constant. Second, major changes in climate may produce periods when the number of individuals of a species will increase to a new higher carrying capacity and periods when that number will decrease to a lower carrying capacity. Third, when a species transfers into a suitable environment where it was previously absent, it will tend to increase geometrically as an exotic (and may provide a growing food supply for some other species), until the new environment is filled (or in most cases overfilled, at the expense of native life forms). And fourth, all species had a beginning and presumably will have an end; therefore there must have been a time when their numbers increased and there will be a time when their numbers will decrease to zero. And, of course, we must include a fifth exception to the law of zero population growth: a species that can radically change the environment and methods of production by cultural rather than biological chance (that is, humans) is capable of greatly expanding production and thus accommodating vast increases in population.
By the time of the 1830 restatement of his Principle of Population, Malthus had become aware that people in some areas of Europe had reduced their fertility in spite of the apparent fact that they possessed sufficient food for larger families. That is, an adequate food supply caused people to reduce their fertility, rather than (in keeping with his theory) increase the number of children they have. He quotes M. Muret regarding the reduction in the fertility rate in Switzerland: “But whence comes it that the country where children escape the best from the dangers of infancy, and where the mean life (income)...is higher than in any other, should be precisely that in which the fecundity is the smallest? How comes it again, that of all our parishes, the one which gives the mean life the highest, should also be the one where the tendency to increase is the smallest?” (p. 64). That is, the tendency for fertility to be inversely related to income, which we recognize as almost universal today, was already apparent in 1830.
Muret (and Malthus) was confused by this relationship between fertility and the food supply. Muret stated that he would hazard a conjecture that: “God has wisely ordered things in such a manner as that the force of life (income) in each country should be in the inverse ratio of its fecundity”... so that the better off will not over-people themselves and the poor by their extraordinary fecundity, will be able to sustain their population (p. 64). Malthus did not appear to agree with Muret that lower fertility among those with better access to food was caused by lower fecundity, but simply saw the Switzerland case stated by Muret as an exception to his theory. He stated: “There can be little doubt that in this case the extreme healthiness of the people, arising from their situation and employments, had more effect in producing the prudential check to population than the prudential check in producing the extreme healthiness” (p. 64). That is, healthiness (higher incomes or better access to food) seemed to be the cause rather than a consequence of lower fertility—reversing the lines of causation in his model.
Nevertheless, Malthus did not see this as evidence that his theory was incorrect. He noted (with regard to Switzerland): “There is no land so little capable of providing for an increasing population as mountainous pastures. And that: ...the actual progress of population is, with very few exceptions, determined by the relative difficulty of procuring the means of subsistence and not by the relative natural powers of increase...” (p. 65). That is, Malthus mostly rejected the idea that people with higher incomes would tend to reduce their fertility except as preventive checks intended to prevent future impoverishment. He held to the notion that checks on population were mostly related to an insufficient food supply (positive checks) or fear that population growth would produce such an insufficiency (preventive checks). In the case of Switzerland and other healthy populations in Europe, he believed people used preventive checks (the prudential restraint on marriage) to prevent over-population and thereby assure that their offspring will share their healthy lifestyle.
According to the Malthusian Theory population growth is a dependent variable (dependent upon an increase in food), and growth in the food supply is an independent variable (independent of population growth). If we were to graph the relationship between the number of people and the amount of food according to the Malthusian Theory, we would put population on the Y-axis and the food supply on the X-axis, to indicate that an increase or decrease in the food supply would lead directly to a concomitant increase or decrease in the population.
Critique of the Malthusian Theory
With the advantage of hindsight we know that Malthus was wrong about the disinclination of humans to limit their population growth unless forced to do so by scarcity or the threat of future scarcity. European people the world over, and more recently most Asians and Latin Americans, have greatly reduced their rate of growth even though they could easily support much larger populations. Indeed, declining fertility around the world is more closely associated with abundance than scarcity; it is the middle and upper classes that are more inclined to reduce their fertility, and the poor who appear most resistant to that change (as was observed in the early 1800’s in Europe by Muret). And indeed, it is mostly those populations with ‘cradle-to-grave’ government care that now experience negative rates of population growth. We also have anthropological evidence that hunter-gatherer societies maintain their populations well below the carrying capacity even though higher fertility rates are clearly possible. We must agree that it is possible that there were times and places where people did or do reproduce as rapidly as possible until they reach the carrying capacity and face poverty or starvation. Nevertheless, we have no definitive proof that this was or is true. Therefore, anyone who holds the view that some people reproduce until they reach carrying capacity, has a very large burden of proof to show why those people behave in a manner so startlingly different from Europeans, Asians, and Latin Americans who clearly have not behaved in that way.
Malthus also knew that, in contrast to other animals, humans could increase their numbers without additional space by changing their method of producing food. Other species can only accomplish that by biological change, which is very slow; humans do that by cultural change that can be very fast. Obviously, he was aware that the population of England was growing, and he knew there had not been a previous die off, nor did England gain access to additional farm land. England was able to feed more people because of new methods of production. Nevertheless, he assumed that possible improvements in farming methods were severely limited and such innovations would at best provide a temporary arithmetic increase in food production.
Over the past 200 years increases in agricultural production proves Malthus’ assumption that such increases would be temporary was wrong. The human population has grown geometrically over the past 200 years, and the pace of technological change in agriculture has been more than adequate to maintain a rate of increase in food production equal to or exceeding the rate of population growth. There can be absolutely no question about this: Malthus has been wrong so far! The world population has doubled three times since Malthus wrote his essay, and notwithstanding that eight-fold increase in numbers, the percentage (not just the number) of the world population very well fed (or overfed) has never been higher. No one believes technological change can make the food supply infinitely large, but only a great fool thinks no further increases in production are possible.
A second critique of the Malthusian Theory is based on biological evolution. We now know that symbiotic relationships that develop between life forms is driven primarily by evolution. Animals tend to scatter the seeds of those plants they gather, causing plants to favor those characteristics preferred by the gatherer rather than characteristics that would favor seed dispersion by wind. Similarly, the mutual dependency, or symbiosis, that develops between animals is driven by evolutionary processes. We refer to those plants that become symbiotic with humans as cultigens, and animals as domestics. However, the evolutionary processes that produce symbiosis between life forms is not confined to humans. Birds plant many of the trees and shrubs that produce the fruits they consume; that is, the seed passes through the digestive system of the bird and is expelled (and fertilized) some distance away. Indeed, the purpose of a nutritious ‘fruit’ surrounding a plant’s seeds is precisely to attract an animal to consume it in order to disburse the seed. Notice that seeds tend to be toxic or bitter, so that the consumer spits them out, or have the ability to pass through the digestive system of the consumer and remain viable when planted and fertilized (for example tomato seeds passing through humans). Squirrels save nuts in an underground cache, which (because of their high mortality rate) they often fail to retrieve, and thus plant. Notice that nut trees prevent consumption of their seeds by large grazing animals (that would not plant them) by producing a very hard shell around the seed, or a poison spot (such as the buckeye tree), which the squirrel can easily open or chew around. Obviously, domestication differs for humans because they become aware of the process and take measures to speed and control it. But, that awareness must come many thousands of years after the evolutionary process has been underway.
The fact that the two postulates Malthus used to support his theory have proven to be false means his logical deduction (that increased production is the cause for population growth) is not necessarily true. However, it is possible that Malthus’ deduction is true for reasons other than those he articulated, or that they are true in some places but not others. For example, if the production systems that have provided for the vast increase in the world population cannot be maintained in a sustainable manner, then the Malthusian Trap has simply been postponed, rather than avoided. Nevertheless, Neo-Malthusians have a heavy burden of proof to explain how and why some human populations will tend to increase their numbers until they reach the carrying capacity and face starvation, and why population growth will not stimulate the development of technology needed to allow production to increase, as it has in the past. Likewise, sustainability has always been a work in progress; we need some theory or evidence to suggest that people will be unable or unwilling to correct the deleterious impacts of their production methods, as they generally have in the past.
In hindsight it is difficult to understand how Malthus could have been unaware of the power of innovation and new technology. After all, he lived in the very heart of the industrial revolution. Nevertheless, before we become too critical of Malthus, we must ask ourselves: How can some modern scholars believe the earth has now reached the limit on food and other production, believe the land and raw materials will soon be used up, and believe there cannot be new ways of doing things? Modern Malthusianist Paul Ehrlich (who wrote The Population Bomb in the late 1960’s) stated (in his widely read Playboy interview, Aug. 1970) that Malthus was essentially correct, he just got his timing wrong (by not anticipating the flood of innovation that accompanied the industrial revolution). Ehrlich stated: “we now know almost exactly what future innovations are possible” [what an incredible statement!], and given the most optimistic assessment they could not possibly provide for the growing human population beyond a few more years. Ehrlich predicted mild food rationing in the U.S. by 1975 (by which time most of the darker skinned persons in Africa, Asia, and Latin America would have mostly starved), with the world population declining to two billion by the year 2000, and leveling off at perhaps one billion later. He also predicted that we would run out of many minerals and other raw materials so that the modern industrial system would cease to operate. Ehrlich was totally wrong about everything he wrote in his book and stated in his Playboy interview; however, that has not diminished his giant stature within the radical environmental movement. Of course, pessimistic futurists have always looked into the bag of future innovations and, finding it empty, declared that no such innovations could be possible; said another way, pessimistic futurists are not innovators!
 V. Gordon Childe, Man Makes Himself, New York: New American Library, 1951.
 Environment creates form: Notice that fish, sea mammals (seals, dolphins, whales), and sea birds (penguins), all have the same shape—designed by their ocean environment. Likewise, the club reversed the thumb to the hand. Chimps can use clubs, but obviously they have not used them long enough to fully oppose the thumb to the hand. And, there is no way early humans could have survived on the savannas without weapons that would allow them to compete against the very aggressive predators and be able to kill the large animals that inhabit that climate zone.
 The ‘marginal return’ to labor is the additional increase in production resulting from the last worker; the economic Law of Diminishing ‘Marginal’ Returns to labor affirms that at some point an additional worker will necessarily produce less. Take the extreme case: a plot of land may require at least two workers to achieve a harvest; thus hiring the second worker may result in increasing ‘marginal’ returns. A third worker may also increase total returns, but not as much as the second worker. The third worker would be hired only if the lower return exceeds the wage. Likewise, a forth worker on the same plot may also increase production, but not as much as the third or second. We say the wage (plus benefits and administrative costs) must equal the marginal return to labor. At some point, hiring an additional worker will not compensate the owner sufficiently to pay the wage; and, of course there is a point at which an additional worker will result in no additional return. After the ‘marginal return’ to labor begins to decline, obviously the average return per worker will also decline.
4 When we graph the relationship between two variables we place, by convention, the independent or cause variable on the X or horizontal axis and the dependent or result variable on the Y or vertical axis. For example, if we plot the relationship between income and life expectancy we would place income on the X or horizontal axis and life expectancy on the Y or vertical axis, suggesting that higher incomes causes increased life expectancy (because of better health care, and because we see no reason why longer life expectance would cause higher income).
 I am not suggesting that plants and animals design their evolutionary processes purposefully to achieve some desirable goal. Some plants and animals lucked into a superior method of spreading their seed or increasing their food supply through the evolutionary process of symbiosis with other life forms; that process does not require purposeful action or even awareness. I am suggesting that the same evolutionary processes explain the domestication of plants and animals by humans as well.
 I attended a conference at La Selva research station in Costa Rica in the early 1980’s at which Paul Ehrlich was present. At one point a Costa Rican scholar was presenting a paper dealing with some aspect of tropical biology. Ehrlich interrupted the presentation with the question of why Costa Ricans were not dealing with their ‘overpopulation’ problem. The question was in such poor Spanish that only an English speaker with some knowledge of Spanish or a Spanish speaker with some knowledge of English could have understood. The man responded that he did not believe Costa Rica had an ‘overpopulation’ problem, and that was not the topic of his presentation. Ehrlich continued his questioning until the gentleman finally gave up his presentation and sat down. I know that many persons in attendance were very upset by that outburst. Perhaps some subscribed to Ehrlich’s ‘Population Bomb’ theory; but we all knew that to challenge Environmentalist Saint Paul Ehrlich would be a fatal mistake.