Plato and Aristotle on living well and optimal population

The ancient Greeks have exerted tremendous influence on western thought and culture, including in the realm of ethics. Yet few today realize that the founders of western political philosophy advocated a steady-state economy and limits to human numbers.

by Theodore P. Lianos

In the fifth century B.C., the Athenian philosopher Socrates (470-399) changed the course of philosophical endeavor from Mathematics and Physics towards a new field: Ethics. For Socrates the basic question of philosophy was a simple one: how should we live?

Socrates’s student, Plato (427-347) wrote two treatises to provide answers to this basic question. He eventually considered his famous Republic (Politeia) written around 380 B.C. as too advanced for the time, and thus later in life he wrote Laws (Nomoi) which he considered second best but immediately applicable.

Plato’s student Aristotle (384-323) in his Politics (Politica) written sometime after 336 B.C. gives, in book VII, his model of a city-nation that would have the “most desirable mode of life”.

Plato (left) and Aristotle (right)

Plato’s vision

Plato expounds his model by imagining the creation of a new colony. The first thing to do, he argues, is to “let the citizens at once distribute their land and houses and not till the land in common, since a community of goods goes beyond their proposed origin and nurture, and education” (Laws, 740, A). The distribution of property should be such that there would “be no disputes among citizen about property” (Laws, 737,B).

The next task is to determine the number of people and the amount of land. These must be determined simultaneously so that two requirements are satisfied: first, citizens must have a decent standard of living, and second, the size of the population must be large enough to be able to defend the city and also help neighbouring cities. In Plato’s words,

“The number of citizens can only be estimated satisfactorily in relation to the territory and the neighbouring states. The territory must be sufficient to maintain a certain number of inhabitants in a moderate way of life—more than this is not required; and the number of citizens should be sufficient to defend themselves against the injustice of their neighbours, and also to give them the power of rendering efficient aid to their neighbours when they are wronged” (Laws,737,C,D).

What is important in the relation between population and land is that they form a common factor, or they become a pair. Plato’s text says “so that every man may correspond to a lot.”

Plato’s central idea here is that land and population should be determined simultaneously in such a way that citizens might enjoy a good but moderate standard of living and the city should be safe from enemies.

What makes this model a steady-state economy is the following requirement, strongly stated by Plato:

“And in order that the distribution may always remain, they ought to consider further that the present number of families should be always retained, and neither increased nor diminished” (Laws, 740, B).

In other words, population must be constant. Plato suggests several ways that this can be done. The farm should be inherited by only one child so that the property would not split. Incentives, disincentives and proper advice may be given to encourage or discourage changes in population as needed. Finally, if necessary, immigration or emigration may be allowed.

Plato recognizes that although all citizens may have equal opportunities to begin with, wealth inequalities may arise. Regarding the question of the level of economic inequality that should be allowed among citizens, Plato proposes that the richest citizen be no more than four times richer than the poorest and any excess wealth, however acquired, should be turned over to the city.

“The citizen must indeed be happy and good, and the legislator will seek to make him so; but very rich and very good at the same time he cannot be, not, at least, in the sense in which the many speak of riches. For they mean by ‘the rich’ the few who have the most valuable possessions, although the owner of them may quite well be a rogue.” (Laws, 742, E)

Thus, Plato’s answer to Socrates’s question is that we should live in a safe environment enjoying a moderate lifestyle. Given that land is limited, the moderate way of life can be achieved by determining and keeping constant the right size population. Economic equality or inequality within limits is also important in a good society. The question may be raised what is a “moderate way of life”. Plato uses the Greek word σώφρων (sophron) which means wise, sensible, prudent, reasonable and judicious. Of course, none of these meanings can be measured objectively in meters or kilos, but certainly in every society at any given time there is a common feeling of what is a moderate way of life.


Aristotle’s refinements

In his own analysis of the relationship between population and land, Aristotle introduces several new elements. First, instead of a moderate way of life he suggests the notion of the “best life,” which presupposes both virtue and a degree of material wealth:

“But a better definition would be ‘to live temperately and liberally’ (for if the two are separated a liberal mode of life is liable to slip into luxury and a temperate one into a life of hardship), since surely these are the only desirable qualities relating to the use of wealth” (Politics 1265a 33-38).

In modern terms we may say that we should live comfortably but not wastefully. The attribute of best life refers both to individuals and to the state.

“For the present let us take it as established that the best life, whether separately for an individual or collectively for a state, is the life conjoined with virtue furnished with sufficient means for taking part in virtuous action” (Politics 1323b40-1324a2).

For Aristotle there is nothing wrong with wealth, it is the use of wealth that can be good or bad. The possession of wealth is desirable, but only insofar as it is put to good use. However, the amount of property sufficient in itself for a good life is not unlimited (Politics 1256b 30-34). The external goods have a limit, as has any instrument (and everything useful is useful for something), so an excessive amount of them must necessarily do harm, or do no good, to their possessor. (Politics 1323b7-10).

According to Aristotle the size of the population of the city should be within limits. The lower limit is that below which the autarky of the city is lost and thus the reason for its creation and development is negated. The upper limit of population size is determined by considerations related to the effective administration of the city. If the population is too large, it will be difficult to run the city effectively and to enforce the law. For example, it would be difficult to find a town crier with a stentorian voice. Also, in an overcrowded city it would be difficult to make the correct decisions regarding the distribution of public offices according to merit, since this requires adequate knowledge of the abilities of individual citizens. Contrary to Plato who specifies the exact number of farmers, Aristotle provides no exact limit except in one case by way of an example:

“You cannot make a city of ten men, and if there are a hundred thousand it is a city no longer. But the proper number is presumably not a single number, but anything that falls between certain fixed points” (Nicomachean Ethics 1170b 30—33).

For the regulation of population, Aristotle thinks that “there must be a limit fixed to the procreation of offspring” (Politics 1335b23-24). Also, he suggests that “it is fitting for women to be married at about the age of eighteen and the men at thirty-seven or a little before” (Politics 1335a28-30). The last suggestion is made for population health purposes, but is clear that it can help limit population growth. He also suggests for the same purpose that “persons exceeding this age [of fifty for men] by four or five years must be discharged from the duty of producing children for the community” (Politics 1335b22-24). It is characteristic of the significance Aristotle attributes to population control that he suggests that “if any people have a child as a result of intercourse in contravention of these regulations, abortion must be practiced on it before it has developed sensation and life” (Politics 1335b24-25).


A message for our times

The ideas of Plato and Aristotle on optimal population size can be understood better in the historical context of their time. As can be surmised by their colonization of the areas around the Mediterranean Sea, many Greek city-states were overpopulated. The population of Greece in the fifth century B.C. is estimated to have grown to three million.

The word land should be taken to mean, in modern language, resources for the production of commodities. Technology of production is not mentioned and is implicitly assumed to be constant, but changes in technology can be easily introduced in the two models presented above.

Both philosophers are very much concerned with social justice and the happiness of citizens as individuals, and also as a totality which forms society. In modern times it is implicitly assumed that higher income brings happiness or that it is a precondition for achieving happiness. For these ancient writers, much wealth is not a precondition for a happy life. Of course, it should be high enough to allow a temperate and generous life-style but happiness is almost synonymous with virtuous action.

The ideas of Plato and Aristotle are not just history. Their message is relevant to our time. We have exhausted the resources of our planet and our efforts to increase production lead us to catastrophic practices (e.g. deforestation). At the same time three billion people (38% of the world population) are undernourished. It is not an exaggeration to say that we have led ourselves into a dramatic and nightmarish situation which is getting worse as the world population increases by approximately 200 thousand every day. As Plato and Aristotle taught, political wisdom is inseparable from an appreciation of limits.

A crowded street in Athens, Greece. Photo: Hert Niks

This piece is a summary of Theodore Lianos’ article Population and Steady-State Economy in Plato and Aristotle, published in The Journal of Population and Sustainability.

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11 thoughts on “Plato and Aristotle on living well and optimal population

  1. Since Wall Street is always chanting the mantra of “We must have growth,” I suggest everyone boot up and read FAMOUS ECONOMIST Adam Smith’s essay on growth and how it is imperative to reach “optimum” populations, for efficiency (such as in providing good healtcare) but then to stop growing or risk consuming all essential resources.

  2. Try explaining the current madness to them – where the very recent explosion from two billion to eight billion is globally applauded as an achievement for humanity. The ancients didn’t really think much about “billions”, especially not as regards human-lemming numbers, although in other contexts they did ponder their myriad myriad (100m), or even higher numbers.

    “But what do your wise philosophers say of all this?” they might finally stutter. You’d have to break it to them gently, today’s academic “philosophers” are kind of out of the loop. And the world is run instead by “economists” and “religionists”, with the UN as their chief propagandist.

  3. What did Plato and Aristotle say about other critters?
    Should they be allowed some habitat?

  4. Greece had lions back then. Other critters running out of habitat might not have been a problem back then.
    However, Plato did say something about the deforestation of Attica.

  5. “Both philosophers are very much concerned with social justice and the happiness of citizens as individuals” – well, yes, but that only applied to free male citizens, not to slaves, not to women.

  6. Aristotle’s Golden mean and Buddha’s middle path are the two ideas which I think would do wonders if propagated on large scale. UN’s Lifestyle for environment (Life) initiative had very little or no coverage in media around the world. Family planning and small family sizes (assuming nuclear family) should be included in this initiative if not already. I think awareness about true happiness being in satisfaction rather than material over consumption and growth, can be a key. Love, Sacrifice and Compassion are some of the values which are important for true satisfaction. Families in which parents are almost always outside working to provide for their family would find it difficult to experience this values. Families with fewer ( at most 2) children would find it easier to promote this values to their next generation and provide them financial support and freedom to fulfill their aspirations. Again which will provide them with satisfaction which consequently would lead to happiness as this aspirations are most likely to be reflection of those values taught.

    1. I think our focus on the nuclear family might also be a problem. The Greek family definitely wasn’t ideal (women were locked up in the house, especially in Athens), but a rich social, political and intellectual life was accessible to all free men and some women, and very fulfilling. Their philosophy, art and drama inspires us to this day.
      Many think that marrying and having children is the only way to have love, purpose and companionship in life, and while that might be true to some very family-oriented people, there are many other ways to live a good life – activism, friendships, extended families, of course nature…

      1. Yes, let’s hope that the things you listed activism…, will be aspired by next generation in greater numbers. But current generation (except sections of developed world) is dominated by institution of family and marriage. To develop good thesis for less children inside this current family structure is imperative towards the cause of population control or optimal population ( especially in
        countries like Pakistan, Nigeria,etc).

  7. Niraj, I agree.
    For those who do want children, we should encourage them to only have one or two, at least for now. For those who don’t or are not sure, we need to show that there are many ways to live a meaningful life and to love and be loved, which is what everyone wants in some way.
    Not having children should not considered taboo, selfish, or conducive to an empty life.

  8. This is extremely important, because both Plato and Aristotle are highly regarded nowadays. But it seems that, as usual, current Dogmas are selective about the bits of Plato and Aristotle that they like. So unless we have ploughed through every word, as the heroic Theodore Lianos has done, we are not aware that they contain such sound common sense about “The Tragedy of the Commons” as it has been dubbed by later Empires.
    The same is true of many revered ancient writings, including the Old Testament. Inconvenient passages in them, containing stark realities, are excised by our prevailing Dogma of Economic Growth. Previous civilizations have often warned against overpopulation, because they witnessed the savage outcome of Overshoot – Famine, Desertification, Plague, and War, forcing emigration and/or colonization in a desperate search for fresh pastures. But eventually even emigration is not a solution and the civilization crashes and only a Remnant is left. This Remnant goes back to living sustainably – because it has to, it has no choice. At least for a few centuries, till the folk memory of the Collapse and why it happened has faded.
    There are quite a few Overshoot philosophers and “Collapsologists” on youtube, but they are not household names of course. Some are systems analysts like Dennis and Donella Meadows, some are financiers and actuaries (maths superbrains i.e.), some are ecobotanists, some are geologists, most are probably some form of biologist. The most high profile at the moment is probably William Rees. Although he probably has not had time in his busy life to read Plato and Aristotle, I am sure he would welcome the fact that his insight into the Limits of Growth (which came from being a farmer in a farming family intially) echoes back down the centuries.
    Thanks to discovering Nate Hagens (an ex-financier) and his many kindred spirits whom he counts as friends, and hosts conversations with on youtube, I have very recently understood in cold maths what will bring our current Overshoot to an end. It is the end of Fossil Fuels that will bring it crashing down – is already starting to. It is Fossil Fuels that have turbo-charged Growth over the past two centuries – but now they are nearly all gone and there is no alternative that could even begin to provide such vast “horsepower” (Energy turning into Work). Slowly at first, but then with increasing rapidity, all the fossil wealth that has bestowed our current “Progress” will be withdrawn, as it would take thousands of years to regenerate. [The same is true of groundwater, by the way, another form of natural “capital” in constant overdraft.]
    Russia and Saudi Arabia remain major exporters of oil and gas, but for how long? And the competition for their exports is getting fiercer by the day. It is not only the Great Powers that have become hooked on Fossil Fuels – most of the world is hooked now, including the very poor.
    Maths geniuses are not shy about stating firmly that the current war between Russia and NATO is about Fossil Fuels and other Raw Materials, as is all the diplomatic skirmishing between the West, China, India, Russia, Saudi Arabia and other players at the UN with a measure of influence (e.g. Japan and the EU). This is not because Maths geniuses are hard-hearted – it is just that the relentless truth in undoctored numerals trumps all considerations of politeness and soft-soaping.
    The reason William Rees and others are desperate to make what is only Common Sense much more public, is that they consider that all Nations should be preparing for the imminent demise of Fossil Fuels and its aftershocks. They consider that no Nation is preparing. At least not at Government level – of course each Nation contains many people who can see what is on the way, as it is all too obvious if you take off your Growth blinkers. But you are often written off as crazy by those still wearing Growth Blinkers, so most people can’t be bothered to preach – they just go off and start to prepare on their own. Which may be all that is possible, in the end – maybe no-one is ever going to persuade either Officialdom or the General Public that Growth is over, whether we like it or not. “Green” Energy cannot deliver Growth – it cannot even maintain the status quo of “Progress”. Neither can nuclear power, or any other “alternative”.
    Therefore, whatever anyone does or does not do, De-Growth is not going to be a choice we make – it is going to be forced on us. People have got used to having Choices, even if they are small farmers growing tea or coffee or other cash crops – but those Choices depend on cheap and plentiful Fossil Fuels, as all our “Choices” do. Including our “Choice” to grow exponentially as a species, or rather sub-species. Nature simply does not allow living creatures to outgrow their available sources of life, and the fact that Mankind has managed to exterminate far more species than Nature ever has – with the aid of Fossil Fuels – does not mean that Mankind is exempt from Nature’s “tyranny”. Because Mankind cannot create Fossil Fuels,or any other vital Raw Materials which can supply the kind of Energy we now need.
    Lie upon lie has to be told by us to ourselves, to disguise this fact – and the mountain of lies now stretches to the moon or even farther. “Family Planning” is just one of those lies. Enough already. It is not “Family Planning” that is going to stop Overshoot, but mass infertility and other pollution-driven ill health, along with a Polycrisis containing other hideous realities. But if Overpopulation gurus want to jmagine that Family Planning, or any other kind of Planning, will save the day and mean that humanity remains IN CONTROL, they are free to do so of course. Artificial Family Planning seems to rely on a huge number of artefacts dependent on Fossil Fuel Energy, for a start, unless it is the plain old “Rhythm Method”.or some other “primitive” method which engenders no monetary profit for anyone and therefore has been deemed not to work. The environmental cost of condoms alone must be staggering – has anyone ever totted it up, including waste disposal? Then there are all the other gadgets.

    1. Excellent summary, William Rees & Nate Hagens are indeed on top form on this subject.

      I imagine this article has been on this site before, but worth revisiting.
      A sustainable human population is about 35 million, and that on a fully functioning planet as was. If they all want to live like current middle class Americans, then 650,000 is the maximum.

      One thing that is often overlooked is carrying capacity – you can have any population you want, but not forever – it is the sustainable population that is the key.
      Over on Twitter Jim Massa (who does Arctic ocean science) stated recently he reviewed all the 40 academic papers on carrying capacity he could find, and they all averaged out at around 100 million for a world population.

      Although I fear now that we’ve damaged the planet so much, and we are in the middle of a mass extinction event, that humans have become functionally extinct.

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