Global Population:



Overpopulation & Abortion On Demand:


by Dr. Julio Gonzalo

Full Professor & Emeritus Professor of Physics

Universidad Autónoma de Madrid - UAM and Universidad San Pablo CEU Madrid


 Dr. Manuel Alfonseca

Full Professor of Electrical Engineering

Universidad Autónoma de Madrid - UAM , Madrid, Spain


 Dr. Felix F. Munoz

Full Professor of Economics

Universidad Autónoma de Madrid - UAM, Madrid, Spain



Link for Citation Purposes:



Fifty years ago, the Club of Rome made news all over the world when it proclaimed that planet Earth was overpopulated and that drastic policies were needed to avoid incoming catastrophic results such as scarcities in vital resources, worldwide criminality increase, environmental deterioration, poverty all over and other dreadful calamities. Here we ask: Was the world really overpopulated in 1972? Is the world really overpopulated now? As it is well known fifty years after the Club of Rome declaration “abortion on demand”, “euthanasia”, same sex “marriages”, massive “gay pride celebrations” all over Europe and America and related activities, have become the “new morality” which is not so different from the old immorality. On the other hand, it's not the right to life the very first human right? The new morality is based upon a materialistic worldview. The traditional old morality is based upon the common sense culturally inherited from Greece and Rome and upon the Ten Commandments he inherited from the Jews, which were for millennia the common heritage of Jews Christians and Muslims. And this heritage has been culturally respected also by Hindu, Buddhist, Confucian and Taoist believers in ordered Cosmos well above purely materialistic Chaos.


1. Introductory considerations

Arturo Peccei, president of the Club of Rome (and co-workers) made news worldwide in 1972 when he said that our planet was overpopulated, and that consequently revolutionary policies were needed to avoid coming catastrophic consequences.


It is not very well known however that quantitative estimates of world population made in advance by the United Nations for 2002, 2005, 2010, exceeded by more than 1.000 millions the actual population actually register when the years 2000, 2005, 2010 arrived. In other words, the projections were systematically much larger, and they were gradually decreasing as the year in question was finally approached.


In a historical perspective, it's clear that a scientific revolution had taken place at the beginning of the 20th century due to the original formulation and further development of Quantum Physics (Max Planck) and Theory of Relativity (Albert Einstein). (It must be noted that Einstein published first the Special Theory of Relativity in 1906, and ten years later the General Theory of Relativity, in 1916, which he applied the following years to Cosmology.)


Fifty years later this was followed by a technological and industrial revolution. World population grew substantially after the Second World War. In the 21st century after first slowing down, it showed clear signs of approaching a replacement level to take place about 2050, implying a considerable decrease by year 2100 at the end of this century.


Among the causes of the large growth in world population in the second-half of the 20th century we may count such scientific discoveries as nuclear energy, the solid-state transistor, the green revolution in agriculture and the development of genetics, a science triggered by the Augustinian monk Gregory Mendel at the end of the 19th century, and successfully powered by the discovery of the DNA structure using X-ray diffraction by Watson and Creek.


These and other discoveries gave rise to great technological applications such as space satellites, computers, lasers which was develop by advanced medicine on the other hand, and the development of Social Security first in Europe and in the USA, contributed certainly to that large increase in world population which occur after 1950 and beyond.


Of course, the future of world population is very difficult to predict... In particular, economic factors –such as energy consumption and food supply– are of course very important. On the other hand, cultural and spiritual are essential factors. We may take into consideration the marked decrease of population which took place in the Roman Empire after the 5th century a.C. which was not due to food scarcity, but rather, to moral decay. On the other hand, a substantial increase of population in America in the 16th century was due to the discovery of that continent by Castilian and Portuguese ships and to the contemporary pacification of the Mediterranean after the victory of Christian battleships in Lepanto, under don Juan de Austria.  That was the time of the first “globalization” when the ships of Spain went around the world for the first time, commanded by Magallanes and Elcano.



Regarding the time dependence description of world population, it is relevant to take into account “rate equations” formulated in terms of the birth rate (BR) and the death rate (DR) whose solution described well world population P(t). Using available population data, for example using United Nations (UN) data, and making realistic extrapolations by means of the time dependences of birth rate and death rate, it has been shown recently that: (a) assuming an exponential (Malthusian) growth of world population is quite unrealistic; (b) the population density of countries with high per capita in the range 15,000 – 45,000 is five to fifteen times higher than the present average all over the world; (c) assuming a fertility rate of FR ≈ 2.1  children per woman and a life expectancy (LE) proportional to the death rate (DR) at replacement (BR ≈ DR ≈ 1.6 x 10-2) an average LE ≈ 71 years is obtained, which can be correlated with the present negative increase in population at places like Japan and Europe.


It may be noted that the substantial increase in world population P(t) from t ≈ 1950 to t ≈ 2035  is due entirely to the increase in life expectancy in this time period rather than to any hypothetic increase in birth rate of fertility rate, totally inexistent in this time period according to the UN data.


2. What's the word really overpopulated in 1972 and in 2023?

As pointed out previously, the Club of Rome stated dogmatically fifty years ago that the World was already overpopulated.


Let us summarize here the well funded considerations of professor Colin Clark (1905–1989), the British-Australian world renowned economist educated at Oxford and Winchester who taught at the London School of Economics (1928–1929); the University of Liverpool (1929–1930); Research Assistant to the Economic Advisory Council (1930); Lecturer at Cambridge University (1930–1938); Government Statistician, Director of the Bureau of Industry and Financial Advisor to Queensland Treasury; Deputy Director of the Commonwealth Department at labor and industry (1942–1946); Research consultant of the Department of Economics at the University of Queensland (1978–1979); Author of the important bookConditions of Economic Progress” (1940); and was chosen by the World Bank as one of the “world's pioneers of development”.


In Colin Clark's article on “Abortion and Population”, (Human Life Review, Summer, 1976) reprinted with permission in “Word Population: Past, Present and Future” (World Scientific: Singapore, 2016) the following relevant considerations are given:


It is not my custom to comment on articles in the American Journal of Obstetrics and Gynecology (though this journal is welcome to comment on any article of mine). But this convention may perhaps be waived when a leading article does not deal with obstetrics and gynecology, but with politics and economics.


The article in question (October 15, 1975) was the presidential address to the American Gynecological Society by Dr. Louis M. Hellman, M.D., who holds official rank in the Federal Department of Health, Education and Welfare as Deputy Assistant Secretary.


What is novel about Dr. Hellman's address is that, after the usual fervent demands for population limitation, he goes on not only to tolerate, but actively to demand abortion. “No country has reduced its population growth significantly without resorting to abortion… Despite the Supreme Court decision in 1973 legalizing abortions… the issue remains morally and ethically controversial. Public debate continues with an increasing number of legal actions and a variety of proposed legislation. Neither family planning nor AID funds can be used to support or promote abortion.”


Dr. Hellman also mentions sterilization, sometimes enforced by legal, or pseudo-legal, means. “We physicians,” he admits, “have been incredibly lax in the matter, and in rare instances outright cavalier.”


“When I joined the Federal Government five years ago,” states Dr. Hellman, “population and family planning were subjects of high priority to both the administration and the Congress. In the last few years, however, I sense a diminishing concern among our own peo­ple and our own Government about our own population problem, which many believe to be solved, and the world issues … the na­tional will to face population issues continues to falter.” “Retrench­ment of federally funded support… for family planning” will, we are told, “threaten national security.”


It may be added that the Government of India, after receiving world-wide publicity for its program of mass sterilization of men in return for a small sum of money or a transistor radio, found that this program had only a limited effect and was unpopular—politicians addressing meetings were faced by hecklers who asked if they them­selves had been sterilized. Recently India also has reduced expendi­ture on its family limitation program.


The phrase “zero population growth” can have two very different meanings. One is actual equality of births and deaths, i.e., zero population growth in the literal sense. The alternative meaning is that the average family should be at replacement level (i.e., just sufficient to replace the parental generation).


What constitutes replacement level varies of course with circumstances. The principal factor to be taken into account is the proportion of children who may be expected to die before themselves reaching maturity. Thus, among primitive tribesmen, average com­pleted families of six may only just constitute replacement level. In modern communities however an allowance of only three or four percent need be made for children dying before reaching maturity. Then an allowance must be made for the minority of women who will remain unmarried—that is, if we are considering the required average offspring per marriage. Finally—a factor often forgotten— we must allow for the male surplus at birth. On an average (for biological reasons not known) there are 1.06 male births for every one female. So, even if there were no child mortality, and no women remained unmarried, it would still require 2.06 offspring to replace two parents. Taking all factors into account, it appears that an average of about 2.2 offspring per marriage is required to replace the parental generation. The U.S.A. appears now to be at or perhaps below this level. (The determination, from currently available statistics, of expected average final completed family is an awkward problem in mathematics, for the solution of which several alternative methods are available. Solution is not helped by the extremely late publication of some important vital statistics).


Some people still find it difficult to grasp the proposition that, if births are actually equal to deaths, population in the future is certain to decline, for the simple reason that births will then only be replacing the much smaller generation born on the average some sixty or seventy years ago. (The only exception to this rule would be a country like Ireland, where the generation born sixty or seventy years ago was larger than the present generation, so current equality between births and deaths would mean that the population would be certain to increase—if they did not emigrate).


So we have the concept of “demographic momentum.” Dr. Hell-man complains that, even with American families now at or below replacement level, some population growth, though gradual, may be expected to continue for the next sixty or seventy years.


For other countries, however, strikingly different results are obtained. General Draper, President Nixon's appointment as U.S. spokesman on the United Nations' Population Commission, at an international banquet (was this really an appropriate occasion?), made the somewhat undiplomatic statement that not only was the United States adopting the policy of zero population growth but that Latin America was also expected to adopt the same policy by the end of the century. But he did not specify which of the two meanings of the phrase zero population growth he had in mind. M. Bourgeois-Pichat, Director of the French Demographic Institute, made calcula­tions on the two different meanings. If the intention was that Latin American births should literally equal deaths by the end of the century, the average Latin American family, which is now about six, would immediately have to be reduced to about one-tenth of its present size. If, on the more plausible but still extremely unlikely assumption that it was expected that the average Latin American family should fall to replacement size by the end of the century, the demographic momentum of the young people already growing up would still cause Latin American population to go on increasing until well past the middle of next century, eventually stabilizing at about three times its present level.


One of the principal reasons for the “faltering” of which Dr. Hellman complains in the United States is the strong opposition now expressed by spokesmen for blacks and other minorities. This has generated an acute crisis in the minds of many fashionable Leftists, who regard themselves as pro-black, but who think that the best service that they can render to blacks is to reduce their numbers.


The “population community”[1] (rather an odd title for those whose whole concern is to reduce population) at its First National Congress on Optimum Population and Environment, “was taught a hard lesson by… the blacks who attended the sessions… not firebrand militants but representatives of relatively conservative groups such as Planned Parenthood and the National Urban League… on the last day of the congress the entire black caucus walked out.” Some black spokesmen complain that officially sponsored family limitations represents a deliberate attempt to check their increas­ing relative numbers, indeed of “genocide.”


In the 1880's the pioneer French sociologist Arsène Dumont made the important observation that racial, linguistic, or religious minorities always tended to be more reproductive than the majorities which surrounded them. The reason for this was, simply, that seeing little prospect of social or economic advancement for their children, they had less incentive to limit their number. Dumont observed this among the Basque, Breton, and Italian-speaking minorities in his own country. It is true alike of the American blacks, of Australian aborigines, of Chinese settlers throughout South-East Asia, and of Indian migrants to Guyana, East Africa, and Fiji—in the last-named case, to the point where the minority eventually became the ma­jority.


The outstanding exception, of course, the “exception which tests the rule,” is the case of the Jews, who do not appear to be more reproductive than the Gentile majority which surrounds them. The Jews however are proverbially successful in securing social and eco­nomic advancement for their children.


In the international sphere, increasing American indifference, Dr. Hellman complains, “will pose a threat to our leadership role.” Well may he complain. Accusations of genocide, etc., have become more strident—as many Americans observed with dismay at the Inter­national Population Conference at Bucharest in 1974.


At previous World Population Conferences, the Russian delegates —having conspicuously gone out into the lobby to receive their instructions before they spoke—took a uniform line, namely that Malthusianism was the last, most vicious, and most degraded form of imperialism, designed to destroy the vitality of the peoples of the developing countries. Now our policy in Russia, they continued, is complete economic and social equality for women (including the right, as travelers have observed, to work as builders, laborers, and generally to do most of the heavy work). This having been done, the Russian spokesmen continued, family size fell of its own accord. So far as can be ascertained, the average family in Soviet Russia has now been at or below replacement level for some time and Soviet leaders are clearly concerned. There are, moreover, important regional differences. The Russians, with their keen sense of racial superiority (on which the Chinese have commented unfavorably) observe with dismay the strangely-named non-Russian-speaking peo­ples of Soviet Asia (Kazakhs, Uzbeks, etc.) continuing to multiply rapidly, while the Soviet Europeans are not replacing themselves.


By the time of the Bucharest Conference the Russian attitude had become more ambiguous, and it was left to the Chinese (in spite of the fact that they are apparently making considerable efforts to re­duce their own births, at any rate among the urban population) to take the lead in mobilizing the Third World against the American proposals, which they did with considerable skill. The Conference ended, as will be remembered, with a remarkable alliance between China and the Vatican to oppose these proposals.


The grounds given for the so fervent demands for American and world-wide population limitation are the familiar ones of the sup­posed inability of the earth to provide food, minerals, and energy for increasing numbers. Attention is drawn to hungry countries such as India, Pakistan, and Bangladesh, where there is little or no addi­tional land for cultivation. But there are countries with much denser populations per acre of agriculture land, such as Japan, Taiwan and Egypt, which succeed in obtaining three times as much rice per unit of land as in the Indian sub-continent. In other Asian countries such as Indonesia, and in almost the whole of Africa and Latin America, there are enormous areas of good potential agricultural land still untouched.


The controversy about the world's capacity to supply food, in which I have been engaged for many years, has now (somewhat to my regret) been brought to an end. Dr. Pawley, formerly head of the FAO Policy Committee, addressing the Scandinavian Economists Conference in 1971 (a summary of his address was given in the FAO Journal Ceres, July-August 1971), after making some un­friendly references to my writings, went on to admit that it was far too easy for people like me to criticize FAO, because the truth of the matter was that, in the course of the next hundred years, there should be no serious difficulty about raising food production to thirty or even fifty times what it is now. (Similar conclusions have also recently been published by Wageningen Agricultural University in the Netherlands). My own targets are more modest than these.


In 1949 the United Nations held a world conference on resources, at which I was one of the principal speakers. Recently I looked up the tables of world mineral resources then presented to us, and sub­tracted from them the amounts which we have in fact already mined since 1949. I find that we have already used up the entire world supplies of copper, lead, zinc, and some other minerals. To treat the proved reserves known to mining companies as estimates of final world resources is ludicrous. Mining companies have to earn divi­dends for their share-holders, or borrow money at high rates of interest, and therefore they must apply high rates of discount to their expenditure on exploration, which is very costly. They cannot afford to explore for minerals which they do not expect to use more than fifteen years or so in the future.


It is possible that world reserves of oil will run out in fifty years or so—though we have so often been told this before—and recent high oil prices have led to remarkable intensification of oil search, and economies and substitution in use. But available coal reserves will last for very much longer and reserves of uranium and thorium for generating nuclear power longer still. If, for any reason, we dis­like the idea of being dependent on nuclear power, the energy reach­ing the earth each year from the sun is far in excess of any conceiv­able needs, once we develop the technology for harnessing it.


So far from the threat of over-population, the real threat with which a large part of the world will soon be faced is that of depopu­lation. In countries such as the U.S., there is no indication that the fall in family size, which has already been reduced to the replace­ment level, may not continue. In some European countries, particu­larly Germany, Sweden and Switzerland, births are already a long way below replacement level, and the fall may proceed still further. Since the beginning of the 1960's some much more profound force than the discovery of oral contraceptives (which occurred about this time) has been at work in the Western countries, some feeling of loss of purpose in life, what some social psychologists even call “death-wish.”


The reduction in births which has already taken place during the last fifteen years, writes the French historian Pierre Chaunu, will suffice to produce, by the 1990's, a historical disaster worse than the depopulation of Europe by the Black Death.


*                 *                 *


Jacqueline Kasun (1924–2009), Professor Emeritus of Economics at the University of Arcata, California, was a leading conservative woman, whose remarkable life spanned the globe. She was a devout Christian, a strong and courageous pro-life leader and pro-family leader. After graduating from the University of California at Berkeley, she enlisted the US Army. Eventually she earned a Masters degree and later a Doctorate at Columbia University. She married Lt. Col. Joseph Kasun, and they had two daughters and a son.


Her remarkable book “The War Against Population” (Ignatius Press, 1st  edition 1988; 2nd revised edition 1999; Spanish translation, Madrid, 1993) had a great impact in the USA and throughout the world, in defense of human life, exposing eloquently the false propaganda of “Planned Parenthood”, an organization making money not “planning” fatherhood and motherhood but killing unborn babies via “dilatation and curettage” of the woman's uterus, using a curved knife; “suction” through the cervix from the interior of the woman's womb; pushing into it a strong “saline solution”. Jacqueline Kasun after the 1973 decision of the US Supreme Court founded a “Grandma House” to help pregnant girls in crisis in her city neighborhood. Her book ends up saying: “The idea that the humanity is multiplying around year 1999 at an accelerating rate is one of the false dogmas of our time”.


We reproduce here selective quotations of the last chapter of Jacqueline Kasin’s book, with the permission of his “Ignatius Press”:


The justification for the extent of government involvement in reproductive decisions rests on the contention that the severity of overpopulation in an overcrowded earth demands that people, especially poor people, be educated to control their fertility. The teaching speaks metaphorically of the earth as a “space ship,” or “lifeboat.” We are, the tale continues, spilling over the edges, and an accretion of more people will sink us all” (2nd. ed.: 279).


The population planners are convinced that human beings, especially the poor and the minorities, are incapable of procreating rationally. For them, this justifies that the administrators of the government assume extraordinary powers through “outreach” and “motivation” programs. But very soon they notice that more coercive measures may be necessary.


As for the economic claims of the population controllers, they (the lifeboat metaphor among them) disintegrate under examination. Resources, far from being limited, are abounding. No more that 1 to 3 percent of the earth’s ice-free land area is occupied by human beings, less than one-ninth is used for agricultural purposes. Eight times and perhaps as much as twenty-two times, the world’s present population could support itself at the present standard of living, using presently available technology; and this leaves half the earth’s land surface open to wildlife and conservation areas.”  (2nd edition, p. 281).


As Jacqueline notes, pollution and environmental degradation are not necessarily due to the population growth but, rather, to a lack of political will and to political incompetence. Almost a third of the earth’s land surface is covered by forests and in some nations they are presently growing faster than they are being cut. We all know that trees have been cut and have grown throughout history on our planet’s surface. And many serious scientists consider the panic about the “global warning” menace as transitory as the previous panic about the “coming ice age.” It is not that population causes traffic jams, it is rather, that government economic planning does not work properly.


The claim that a hapless humanity, outbreeding out of control, is falling into misery, is far from true. And the lack of “access” to family-planning “services,” which the population planners have been decrying for years, is not true either. If it were, it is difficult to understand why anti-ovulation pills have been piling up for years in the warehouses of Bangladesh, for instance.


The government family planners aspire not only to exert more control over those whom they ostensibly serve- the young and the poor and the minorities- but also over those who are forced to support the programs by taxation. As an example, the largest private operator of subsidized birth-control clinics, Planned Parenthood, receives little more than a fifth of its support from private voluntary contributions, and part of even that comes from government as payroll-deduction drives among public employees and military personnel. Put succinctly, the government anti-natalists have reached the point where they can press their indoctrination and their services on targeted groups of citizens while taxing them for the privilege.”  (2nd edition, p. 282).


The real demographic problem of the twenty-first century is likely to be the dwindling proportion of young people relative to the old, which will strain social security systems and cause many other problems.” (2nd. Edition, p. 284).


As Jacqueline points out, the inspiration of government birth control is and always has been, eugenic. The booklets of Planned Parenthood, the Gruttmacher Institute and the like are profusely illustrated by dusky women surrounded by lots of children living in slums. The rationale of the eugenic movement is scientific racism. Eugenic policies do not solve social problems, they simply eliminate people.


The government family-planning programs implicitly, but fundamentally and necessarily, assume that the government can, in its wisdom, correct the “mistakes” of private actions, a faulty assumption all the way around. Individual families have always faced real cost restraints on their behavior, including reproduction, unlike government planners, who do not risk their own resources in their projects but shift the costs of their mistakes to others… From urban unemployment to slow growth and environmental degradation, government planners can lay the blame, not on failed plans, but on “overpopulation”.” (2nd. Edition, p. 285).


For family planners, birth control is now and will be in the foreseeable future the final solution to poverty. Their main interest is to maximize the scope of their programs. Planners do not make profits by reducing costs to voluntary buyers, but receive income proportional to the costs they incur in the process of producing goods. It is obvious that it is in the best interest of the subsidized birth control industry to provide as many contraceptives, sterilizations and abortions as possible. To expect otherwise would be to expect them to act against their economic interest.


The real problem of government family planning is not one of families out of control, but of planners out of control.” (2nd. Edition, p. 287).

The planners are inspired by a social philosophy that holds that there is no universal standard of goodness, truth and justice.


The leaders of the population-control movement are the self-appointed interpreters of technological change and social change. They are the enlightened few who are entitled to dictate what changes in beliefs are suitable to the new conditions: the “change agents,” the enlightened vanguard guiding humanity towards a new future.


In the Age of Socialism it has become clear, contrary to the views of prominent birth controllers, that the government does not support the people. On the contrary, the people necessarily work and pay taxes to support themselves and the government. Official data do not reflect the care that families give their own. And official policy does discourage or destroy much of the care that voluntary charity has been giving historically to the poor and the less privileged. People must pay heavy taxes to support social programs that do not work. It is not surprising that population controllers seek to accomplish their agenda through the United Nations bureaucracy, which is even further removed than national governments from truly democratic processes. The environmental agencies of the United Nations, in their aspiration to planned and controlled “sustainable development,” combine the fervor of nature worship with the lack of accountability of an unelected international bureaucracy, as Jacqueline Kasun eloquently shows.


The movement has gained momentum in the centers of power; it has captured the subsidized and politicized educational and research systems with its rationalizations; it has its own publishing and advertising outlets; and it has prodigious public funding and reciprocal political support.” (2nd Edition, p. 290).


As Jacqueline points out, infanticide (once virtually stamped out in Asia) has now returned and is gaining ground in the West, not only for children with Down’s syndrome, but also for social and economic reasons; in the West, the case for the “terminally” ill slips easily from alleviation of discomfort  to “merciful” killing; “important” people will be treated with exotic treatments, but the poor, the politically “undistinguished,” will be classified as “terminal” and will be given expeditious therapy; current trends toward death instruction will accelerate making these new public “services” as common as birth control.


However, the irony is that world is moving towards a leveling population and possibly a population decline after mid Twenty First Century, as implied by the United Nations demographic projections. The international drive to reduce fertility is an effort to bring about something which is already happening anyway. The efforts of the population planners, besides going against human freedom and human dignity, are already producing and will continue producing unwanted and unexpected consequences.


Only a radical repudiation of the philosophy of social panning could reverse the trend.” (2nd edition, p. 294).


This brief summary does not do justice to the full chapter in Jacqueline Kasun’s book, which the interested reader is suggested to consult.



3. Concluding remarks

We think it is highly appropriate to recommend taking a close look to the modeled equation giving the World Population P(t) as a function of time t (years) which describes a step up in population:



Where PRL ≈ 0.8 x 109 is the replacement level world population an t << ti , ti ≈ step up inflation time ≈ 1990 (years), τi is a characteristic time related to the birth rate and the death rate at t = ti and ΔPmax ≈ 7.4 x 109. Therefore, P(t>>ti) ≈ 8.2 x 109 unless a further step down begins to take place.


Eq. (1) describes fairly well United Nations population data from t = 1950 to t = 2025, and allows a realistic estimate of world population going through a maximum at mid twenty first century, followed by a relatively serious decrease of world population around t ≈ 2000.


A population “implosion” would be certainly not desirable.


Let us quote Bernard N. Nathanson MD, an early propagandist of abortion on demand, who later in life became a convinced pro-life MD. In the forward to “The Moral Question of Abortion” (Loyola University Press: Chicago, 1990) he said:


“The book correctly emphasizes that the mere size of a human being is no measure of his/her value; it has long been my contention that in the tiny almost invisible thirty-two cell blastocyst –in the gram or so of tissue– there is a physical potential and moral density unparalleled in our universe. Next to it, a gram of plutonium is a triviality: plutonium cannot compose a symphony, cannot cure a cancer, cannot plan our course to the stars.”






[1] Population Reference Bureau, Population Bulletin December 1970, pp. 18-19