Diamond, Jared ( 2012). The World Until Yesterday: What Can We Learn from Traditional Societies?. New York: Viking. 2012. ISBN 9781101606001. Pagine 512. 13,61 €
Superato il traguardo dei 75 anni, Jared Diamond ha sentito il bisogno di scrivere una summa delle sue ricerche, ma anche delle sue convinzioni. O almeno così penso io, sia perché è una tentazione abbastanza frequente tra gli scienziati e gli accademici al momento di lasciare l’insegnamento e la ricerca attiva, sia perché – benché il filo conduttore del sottotitolo, Che cosa possiamo imparare dalle società tradizionali?, faccia da collante tra i vari capitoli – ognuno dei temi del libro avrebbe potuto costituire a pieno titolo un saggio a sé stante.
D’altro canto, Diamond ci ha sempre sorpreso per la vastità e l’apparente dispersione dei suoi interessi: dopo essersi addottorato in fisiologia sull’assorbimento del sale nella vescica, ha studiato sul campo (e continua a farlo) gli uccelli della Nuova Guinea e delle isole del Pacifico, ma la sua fama è legata soprattutto ad Armi, acciaio e malattie, un’originale sintesi di storia e geografia che gli ha valso un premio Pulitzer per la saggistica e fama mondiale. Lascio che sia la voce di Wikipedia a riassumerne i contenuti per voi:
Il libro è incentrato sulla ricerca di una risposta alla domanda che Yali, un abitante della Nuova Guinea, fece all’autore nel luglio del 1972: “Come mai voi bianchi avete tutto questo cargo e lo portate qui in Nuova Guinea, mentre noi neri ne abbiamo così poco?”, dove per Cargo si intendono tutti quei beni tecnologici di cui i guineani erano privi prima dell’arrivo dei coloni. In pratica l’autore cerca di rispondere alle seguenti domande: perché sono stati gli europei e gli americani del nord a sviluppare una civiltà tecnologicamente avanzata e non, ad esempio, i cinesi o i sumeri? Perché gli europei sono partiti alla conquista degli altri popoli (ottenendo evidenti successi, spesso con tragiche conseguenze per i “conquistati”), e non è avvenuto il contrario? Come mai i fieri guerrieri nativi americani sono stati spodestati dall’invasione di un popolo di agricoltori?
Riunendo in un unico libro cognizioni dalle più svariate discipline, Diamond sviluppa un quadro d’insieme sulla storia delle varie società umane a partire dalla fine dell’ultima glaciazione, avvenuta circa 13.000 anni fa. Per la prima volta, si riunisce nella visione storica un quadro formato da archeologia, antropologia, biologia molecolare, ecologia, epidemiologia, genetica, linguistica e scienze sociali, per non parlare della teoria del caos.
In pratica l’autore cerca di dare una sorta di metodo d’indagine scientifico ad una disciplina considerata finora “letteraria” e di respingere spiegazioni razziste della storia dell’umanità, non tanto per motivi ideologici, ma piuttosto, appunto, scientifici. Consapevole del suo ruolo di iniziatore, precisa che la sua è solo una visione generale, i cui dettagli vanno indagati più approfonditamente.
Non riesco a ricordare in che modo sono venuto a conoscenza di Guns, Germs, and Steel. Ho la prima edizione britannica (Jonathan Cape) e ho la certezza (e la prova) di averlo comprato all’Anglo American Book Co. di via della Vite, a Roma. Ricordo di esserne stato conquistato fin dalla prima pagina del Prologo, quella in cui Yali pone la famosa domanda sul cargo (sapevo già qualcosa sui cargo cults delle isole del Pacifico) e di averlo divorato (il libro, non il cargo).
Subito dopo sono andato a cercare gli altri libri di Diamond: The Rise And Fall Of The Third Chimpanzee (Il terzo scimpanzé. Ascesa e caduta del primate homo sapiens) e Why Is Sex Fun? (Perché il sesso è divertente?). Del primo ho la prima edizione britannica in brossura (Vintage): l’edizione è del 1992, ma io possiedo l’undicesima ristampa e sono certo di aver letto il libro dopo Guns, Germs, and Steel. Non ricordo dove l’ho comprato, ma nell’ultima pagina del testo c’è ancora, come segnalibro, un biglietto della metropolitana di Lisbona del 14 agosto 1998: ne desumo che non posso che averlo letto, o almeno finito, dopo quella data. Sul secondo qualche certezza in più: ho di nuovo la prima edizione, questa volta americana (BasicBooks) e l’ho certamente acquistato su Amazon il 4 giugno 1998: Amazon.com tiene traccia di tutto, e quindi posso raccontarvi che è stato in assoluto il mio primo avventuroso ordine su Amazon; che insieme al libro di Diamond mi sono fatto mandare Girlfriend in a Coma di Douglas Coupland, Visual Explanations: Images and Quantities, Evidence and Narrative di Edward R. Tufte e Timequake di Kurt Vonnegut; e che ho speso in totale, compresi i costi di spedizione, $ 109,87.
Poi ho dovuto aspettare il 2005 per leggere Collapse (Collasso. Come le società scelgono di morire o vivere): di nuovo una prima edizione americana (Viking), di nuovo un acquisto (ormai meno avventuroso) su Amazon.com, il 19 gennaio 2005. Il segnalibro all’ultima pagina è il tagliando di un concerto all’Auditorium Santa Cecilia del Parco della musica di Roma: un Requiem di Brahms diretto da Antonio Pappano il 9 maggio 2005.
Ormai siamo all’epoca contemporanea: perché di Natural Experiments of History, curato da Jared Diamond e James A. Robinson ho scritto una recensione su questo blog qualche mese fa.
Tornando a The World until Yesterday – fatta la doverosa premessa che il libro è sempre ben argomentato e interessante e che la voce di Jared Diamond è inconfondibile e convincente – ho due problemi: il primo è che non tutti i temi affrontati sono, almeno per me, dello stesso interesse; il secondo è che, nel tentativo di rispondere alla domanda Che cosa possiamo imparare dalle società tradizionali?, Diamond a volte dà risposte che nemmeno il compianto Massimo Catalano. Ad esempio: dobbiamo seguire l’esempio delle società tradizionali che rispettano gli anziani (anche perché sono merce rara, mentre da noi sono inflazionati), ma non quello delle società tradizionali in cui si usa abbandonare i vecchi a morire d’inedia o strangolarli direttamente prima di lasciare il campo: «!Jul’joh/ansi, controlla di aver spento il nonno e il fuoco». Ancora: dobbiamo seguire l’esempio delle società tradizionali in cui il bambino non perde mai il contatto con la mamma per i primi 4 anni di vita (per fortuna i miei ormai sono grandi, se no sai che palle), ma non quello delle società tradizionali in cui si pratica l’infanticidio dell’eventuale gemello o del fratellino nato troppo a ridosso del precedente (eppure io, che sono il primogenito e ho una sorella nata 14 mesi dopo di me, quelle pratiche tradizionali le comprendo, anche se non le approvo). Il problema – lo avevamo visto anche nei libri precedenti – è che Diamond è scrupoloso e rigoroso al limite della pedanteria (per quello mi piace!), e ritiene suo preciso dovere fare un sunto degli argomenti e delle argomentazioni alla fine di ogni capitolo, senza lasciare alcun filo pendente …
Tornando al primo dei problemi che ho individuato, penso sia utile elencare i diversi argomenti trattati nei diversi capitoli:
- Amici, nemici, stranieri e persone con cui si commercia
- Guerra e pace
- Cura della prole
- Trattamento degli anziani
- Risposta ai pericoli
- Salute e abitudini di vita
Personalmente, ho trovato di particolare interesse i primi 2 argomenti, il quinto e il sesto e, in parte il settimo.
Sopra tutto, ho apprezzato in modo particolare i racconti autobiografici tratti dalle sue esperienze dirette (Jared Diamond ha fatto una vita veramente interessante e avventurosa la sua parte, anche se non so fino a che punto invidiarlo), mentre sono rimasto freddo ai consigli utili, soprattutto quando si confondono con un salutismo e una political correctness un po’ New Age (guarda un po’: ero convinto che Diamond vivesse nella hippieggiante California, non nell’austero New England).
Ma la cosa veramente importante da portare a casa di questo libro è il concetto (e il principio) della constructive paranoia, di cui si parla spesso, ma segnatamente nel capitolo dedicato alla risposta ai pericoli.
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Le solite citazioni (riferimento alle posizioni Kindle). Potete saltarle, se credete, ma se volete leggerle, armatevi di pazienza, perché sono parecchie.
[…] “constructive paranoia.” […] [665: la prima volta che ne parla è qui]
Traditional societies represent thousands of millennia-long natural experiments in organizing human lives. We can’t repeat those experiments by redesigning thousands of societies today in order to wait decades and observe the outcomes; we have to learn from the societies that already ran the experiments. 
Evidently, traditional trade has social and political as well as economic functions: not merely to obtain items for their own sake, but also to “create” trade for advancing social and political goals. 
Citizens are dissuaded in two ways from resorting to private violence: by fear of the state’s superior power; and by becoming convinced that private violence is unnecessary, because the state has established a system of justice perceived to be impartial (at least in theory), guaranteeing to citizens the safety of their person and their property, and labeling as wrong-doers and punishing those who damage the safety of others. If the state does those things effectively, then injured citizens may feel less or no need to resort to do-it-yourself justice, New Guinea–style and Nuer-style. (But in weaker states whose citizens lack confidence that the state will respond effectively, such as Papua New Guinea today, citizens are likely to continue traditional tribal practices of private violence.) 
One example is the so-called Soccer War of June–July 1969 between El Salvador and Honduras. At a time when tensions between the two countries were already high over economic disparities and immigrant squatters, their soccer teams met for three games in a qualifying round for the 1970 World Cup. Rival fans began fighting at the first game on June 8 in the Honduran capital (won 1–0 by Honduras), and the fans became even more violent at the second game on June 15 in the El Salvador capital (won 3–0 by El Salvador). When El Salvador won the decisive third game 3–2 in overtime on June 26 in Mexico City, the two countries broke diplomatic relations, and on July 14 the El Salvador army and air force began bombing and invading Honduras. 
I sympathize with scholars outraged by the mistreatment of indigenous peoples. But denying the reality of traditional warfare because of political misuse of its reality is a bad strategy, for the same reason that denying any other reality for any other laudable political goal is a bad strategy. The reason not to mistreat indigenous people is not that they are falsely accused of being warlike, but that it’s unjust to mistreat them. The facts about traditional warfare, just like the facts about any other controversial phenomenon that can be observed and studied, are likely eventually to come out. When they do come out, if scholars have been denying traditional warfare’s reality for laudable political reasons, the discovery of the facts will undermine the laudable political goals. The rights of indigenous people should be asserted on moral grounds, not by making untrue claims susceptible to refutation. 
Richard Wrangham argues that two features distinguish those social species that do practise war from those that don’t: intense resource competition, and occurrence in groups of variable size such that large groups sometimes encounter small groups or individual animals which they can safely attack and overwhelm by numbers with little risk to the aggressors. 
Surveys by Louis Harris and Associates showed that American people believe that the elderly are bored, closed-minded, dependent, isolated, lonely, narrow-minded, neglected, old-fashioned, passive, poor, sedentary, sexually inactive, sick, unalert, unproductive, morbidly afraid of death, in constant fear of crime, living the worst years of life—and spending a good deal of their time sleeping, sitting and doing nothing, or nostalgically dwelling upon their past. 
[…] Iban of Borneo […] [3927: una popolazione particolarmente interessante, come i Pin di Celebes e gli Userid di Komodo]
One obvious negative consequence of those demographic facts is that society’s burden of supporting the elderly is heavier, because more older people require to be supported by fewer productive workers. That cruel reality lies at the root of the much-discussed looming crisis of funding the American Social Security system (and its European and Japanese counterparts) that provides pensions for retired workers. If we older people keep working, we prevent our children’s and our grandchildren’s generation from getting jobs, as is happening right now. If, instead, we older people retire and expect the earnings of the shrinking younger cohort to continue to fund the Social Security system and pay for our leisure, then the financial burden of the younger cohort is far greater than ever before. And if we expect to move in with them and let them privately support and care for us in their homes, they have other ideas. One wonders whether we are returning to a world where we shall be reconsidering choices about end of life made by traditional societies—such as assisted suicide, encouraged suicide, and euthanasia. In writing these words, I am certainly not recommending these choices; I am instead observing the increasing frequency with which these measures are being discussed, carried out, and debated by legislators and courts. [3997: certo che questo getta una luce diversa sul dibattito attualmente in corso in Italia]
All of us kept shouting “Tolong!” (Indonesian for “help”), but we were far out of hearing range of the sailing canoes in the distance. [4364: quindi il “Tolong, tolong, tolong, tolong” della leggendaria Mucca Carolina era un disperato grido d’aiuto?]
[…] traditional people have none of the means of passive entertainment to which we devote inordinate time, such as television, radio, movies, books, video games, and the Internet. Instead, talking is the main form of entertainment in New Guinea. 
But there are two other big differences between environmental hazards in modern societies and in traditional societies besides the particular hazards involved. One difference is that the cumulative risk of accidental death is probably lower for modern societies, because we exert far more control over our environment even though it does contain new hazards of our own manufacture such as cars. The other difference is that, thanks to modern medicine, the damage caused by our accidents is much more often repaired before it kills us or inflicts life-long incapacity.
Those two differences are part of the reason why traditional people so willingly abandon their jungle lifestyle, admired in the abstract by Westerners, who don’t have to live that lifestyle themselves.
“Rice to eat, and no more mosquitoes!” was their short explanation. [4769-4774-4779]
The adoption of agriculture enabled formerly nomadic hunter-gatherers to settle down in crowded and unsanitary permanent villages, connected by trade with other villages, and providing ideal conditions for the rapid transmission of microbes. Recent studies by molecular biologists have demonstrated that the microbes responsible for many and probably most of the crowd diseases now confined to humans arose from crowd diseases of our domestic animals such as pigs and cattle, with which we came into regular close contact ideal for animal-to-human microbe transfer only upon the beginnings of animal domestication around 11,000 years ago.
They do have infectious diseases, but their diseases are different from the crowd diseases in four respects. First, the microbes causing their diseases are not confined to the human species but are shared with animals (such as the agent of yellow fever, shared with monkeys) or else capable of surviving in soil (such as the agents causing botulism and tetanus). Second, many of the diseases are not acute but chronic, such as leprosy and yaws. Third, some of the diseases are transmitted inefficiently between people, leprosy and yaws again being examples. Finally, most of the diseases do not confer permanent immunity: a person who has recovered from one bout of a disease can contract the same disease again. These four facts mean that these diseases can maintain themselves in small human populations, infecting and re-infecting victims from animal and soil reservoirs and from chronically sick people. [5043-5048]
[…] kwashiorkor […] [5114: una malattia dovuta alla deficienza di proteine]
The significance of sex and food is reversed between the Siriono and us Westerners: the Sirionos’ strongest anxieties are about food, they have sex virtually whenever they want, and sex compensates for food hunger, while our strongest anxieties are about sex, we have food virtually whenever we want, and eating compensates for sexual frustration. 
A similar modern case of field scattering by Andean peasant farmers near Lake Titicaca, studied by Carol Goland, provoked development experts to write in exasperation, “The peasants’ cumulative agricultural efficiency is so appalling…that our amazement is how these people even survive at all…. Because inheritance and marriage traditions continually fragment and scatter a peasant’s fields over numerous villages, the average peasant spends three-quarters of his day walking between fields that sometimes measure less than a few square feet.” The experts proposed land-swapping among farmers in order to consolidate their holdings.
But Goland’s quantitative study in the Peruvian Andes showed that there really is method to such apparent madness. In the Cuyo Cuyo district, the peasant farmers whom Goland studied grow potatoes and other crops in scattered fields: on the average 17 fields, up to a maximum of 26 fields, per farmer, each field with an average size of only 50 by 50 feet. Because the farmers occasionally rent or buy fields, it would be perfectly possible for them in that way to consolidate their holdings, but they don’t. Why not?
A clue noticed by Goland was the variation in crop yield from field to field, and from year to year. Only a small part of that variation is predictable from the environmental factors of field elevation, slope, and exposure, and from work-related factors under the peasants’ control (such as their effort in fertilizing and weeding the field, seed density, and planting date). Most of that variation is instead unpredictable, uncontrollable, and somehow related to the local amount and timing of rain for that year, frosts, crop diseases, pests, and theft by people. In any given year there are big differences between yields of different fields, but a peasant can’t predict which particular field is going to produce well in any particular year.
What a Cuyo Cuyo peasant family has to do at all costs is to avoid ending up at the end of any year with a low harvest that would leave the family starving. In the Cuyo Cuyo area, farmers can’t produce enough storable food surpluses in a good year to carry them through a subsequent bad year. Hence it is not the peasant’s goal to produce the highest possible time-averaged crop yield, averaged over many years. If your time-averaged yield is marvelously high as a result of the combination of nine great years and one year of crop failure, you will still starve to death in that year of crop failure before you can look back to congratulate yourself on your great time-averaged yield. Instead, the peasant’s aim is to make sure to produce a yield above the starvation level in every single year, even though the time-averaged yield may not be highest. That’s why field scattering may make sense. If you have just one big field, no matter how good it is on the average, you will starve when the inevitable occasional year arrives in which your one field has a low yield. But if you have many different fields, varying independently of each other, then in any given year some of your fields will produce well even when your other fields are producing poorly.
To test this hypothesis, Goland measured the yields of all the fields of 20 families—488 individual fields in all—in each of two successive years. She then calculated what each family’s total crop yield, pooled over all their fields, would have been if, while still cultivating the same total field area, they had concentrated all their fields at one of their actual locations, or if instead they had scattered their fields at 2, 3, 4, etc. up to 14 different ones of the actual locations. It turned out that, the more numerous were the scattered locations, the lower was the calculated time-averaged yield, but also the lower was the risk of ever dropping below the starvation yield level. For instance, a family that Goland labeled family Q, which consisted of a middle-aged husband and wife and a 15-year-old daughter, was estimated to need 1.35 tons of potatoes per acre of land per year in order to avoid starvation. For that family, planting at just a single location would have meant a high risk (37%!) of starving in any given year. It would have been no consolation to family Q, as they sat starving to death in a bad year such as arrives about once in every three years, to reflect that that choice of a single location gave them the highest time-averaged yield of 3.4 tons per acre, more than double the starvation level. Combinations of up to six locations also exposed them to the risk of occasional starvation. Only if they planted seven or more locations did their risk of starvation drop to zero. Granted, their average yield for seven or more locations had dropped to 1.9 tons per acre, but it never dropped below 1.5 tons per acre, so they never starved.
On the average, Goland’s 20 families actually planted two or three more fields than the number of fields that she calculated that they had to plant in order to avoid starvation. Of course, that field scattering did force them to burn more calories while walking and transporting things between their scattered fields. However, Goland calculated that the extra calories thereby burned up were only 7% of their crop calorie yields, an acceptable price to pay for avoiding starvation. [5193-5226]
Far too many American investors forget the difference, recognized by peasant farmers around the world, between maximizing time-averaged yields and making sure that yields never drop below some critical level. If you are investing money that you are sure you won’t need soon, just to spend in the distant future or for luxuries, it’s appropriate to aim to maximize your time-averaged yield, regardless of whether yields become zero or negative in occasional bad years. But if you depend on your investment earnings to pay current expenses, your strategy should be that of the peasants: make sure that your annual earnings always remain above the level necessary for your maintenance, even if that means having to settle for a lower time-averaged yield. 
My childhood was repeatedly punctuated by explosions of the antiquated pressure cooker in which my mother boiled produce before jarring it, spraying vegetable mush over our kitchen ceiling. [5349: a me è successo una volta sola, ma non mi sono mai ripreso]
Finally, one can achieve the purpose of storing surplus food by converting it into some non-food item that is convertible back into food during a subsequent hungry season. 
To borrow a phrase from economists, religion thus incurs “opportunity costs”: those investments of time and resources in religion that could have been devoted instead to obviously profitable activities, such as planting more crops, building dams, and feeding larger armies of conquest. If religion didn’t bring some big real benefits to offset those opportunity costs, any atheistic society that by chance arose would be likely to outcompete religious societies and take over the world. 
“Religion is a set of traits distinguishing a human social group sharing those traits from other groups not sharing those traits in identical form. Included among those shared traits is always one or more, often all three, out of three traits: supernatural explanation, defusing anxiety about uncontrollable dangers through ritual, and offering comfort for life’s pains and the prospect of death. Religions other than early ones became co-opted to promote standardized organization, political obedience, tolerance of strangers belonging to one’s own religion, and justification of wars against groups holding other religions. 
“A language is a dialect backed up by its own army and navy.” 
[…] “coca-colonization.” […] 
A possible victim of this cryptic epidemic of diabetes that I postulate in Europe was the composer Johann Sebastian Bach (born in 1685, died in 1750). While Bach’s medical history is too poorly documented to permit certainty as to the cause of his death, the corpulence of his face and hands in the sole authenticated portrait of him (Plate 28), the accounts of deteriorating vision in his later years, and the obvious deterioration of his handwriting possibly secondary to his failing vision and/or nerve damage are consistent with a diagnosis of diabetes. The disease certainly occurred in Germany during Bach’s lifetime, being known there as honigsüsse Harnruhr (“honey-sweet urine disease”). 
We’ve seen that NCDs are overwhelmingly the leading causes of death in Westernized societies, to which most readers of this book belong. Nor is it the case that you’ll have a wonderful carefree healthy life until you suddenly drop dead of an NCD at age 78 to 81 (the average lifespan in long-lived Western societies): NCDs are also major causes of declining health and decreased quality of life for years or decades before they eventually kill you. 
Another simple change is to eat more slowly. Paradoxically, the faster you wolf down your food, the more you end up eating and hence gaining weight, because eating rapidly doesn’t allow enough time for release of hormones that inhibit appetite. 
[…] you can enjoy some of the world’ greatest cooking and live peacefully and avoid those diseases, by incorporating three enjoyable habits into your life: exercising; eating slowly and talking with friends while you eat, instead of gulping down your food by yourself; and selecting healthy foods like fresh fruits, vegetables, low-fat meat, fish, nuts, and cereals, while avoiding foods whose labels show that they’re high in salt, trans fats, and simple sugars.