giovedì 6 ottobre 2016

Noi e le nanotecnologie

Il premio Nobel per la chimica è stato assegnato a Sauvage, Stoddart e Feringa per i loro studi sulle "macchine molecolari".
La chimica non è certo una materia molto interessante per la maggioranza delle persone ma la sociologia e l’economia sì. E allora, più che chiedersi come funziona una “macchina molecolare” ha senso chiedersi come sarà la società di domani quando le nanotecnologie saranno disponibili.
Per rispondere puo’ essere d’aiuto la lettura di un saggio curato da David Friedman dal titolo “Very Small Legos “.
Ma cos’è una nanotecnologia, detto in parole povere?
… the possibility of maneuvering things atom by atom
Forse non vi rendete conto di quanto sia piccolo un atomo. Indovinate quanti ce ne sono in un grammo di idrogeno? Vabbè, ve lo dico io: 602,400,000,000,000,000,000,000.
Tutti gli organismi possono essere visti come costruzioni ingegneristiche su scala atomica, dal che è facile ricavare l’idea centrale delle nanotecnologie.
… When an atom in a strand of DNA is in the wrong place, the result is a mutation. As we become better and better at manipulating very small objects it begins to become possible for us to build as we are built... That is the central idea of nanotechnology…
Un aspetto interessante della cosa: la resistenza
… Since the bonds between atoms are very strong, it should be possible to build very strong fibers from long-strand molecules…
Un altro: la velocità
… Mechanical parts move very slowly compared to the movement of electrons in electronic computers. But if the parts are on an atomic scale, they do not have to move very far…
Chissà, probabilmente domani “inghiottiremo il chirurgo” che ci opererà…
… Think of it as a robot submarine that goes into a cell, fixes whatever is wrong… “it would be interesting in surgery if you could swallow the surgeon” (Richard Feynman)
Forse domani vivremo in compagnia degli “assemblatori”. Ma cosa sono?
… An assembler is a nanoscale machine for building other nanoscale machines. Think of it as a tiny robot…
Potremmo fabbricare (o far fabbricare dagli assemblatori) un sangue più funzionale per i nostri corpi…
… Ralph Merkle proposed and Robert Freitas further developed an ingenious proposal for an improved version of a red blood cell... Its advantage becomes clear the day you have a heart attack…
Gli scettici non mancano ma i loro argomenti non convincono…
… Some authors arguing that the technology is and always will be impossible for a variety of reasons. The obvious counterexample is life, a functioning nanotechnology based on molecular machines constructed largely of carbon…
C’è poi il solito problema:
… if the design works why don't we already have them?…
E’ un problema evoluzionistico, lo dico in altri termini: se le nanotecnologie consentono davvero un miglioramento di efficienza tanto importante della nostra vita perché mai l’evoluzione ha invece deciso di non concedercelo in modo naturale? Forse l’evoluzione è troppo lenta
… evolution can produce large improvements that occur through a long series of small changes, each itself a small improvement... But if a large improvement cannot be produced that way, if you need the right twenty mutations all happening at once in the same organism, evolution is unlikely to do it. The result is that evolution has explored only a small part of the design space... Hence we would expect that human beings, provided with the tools to build molecular machines, would be able to explore different parts of the design space, to build at least some useful machines that evolution failed to build…
Cosa mi serve per costruire un’auto?
… To build a nanotech car I need assemblers - produced in unlimited numbers by other assemblers - raw material, and a program, a full description of what atoms go where. The raw material should be no problem…
Ah, non dimentichiamoci dell’energia. L’esempio della ghianda è illuminante…
… An acorn contains design specifications cations and machinery for building an oak tree, but it needs sunlight to power the process. Similarly, assemblers will need some source of energy…
L’elemento più problematico – ovviamente – è il software. L’algoritmo attraverso cui la ghianda ottiene la quercia è incasinatissimo.
Un problema tipico dei software è la pirateria: difficile ci si impegni più di tanto quando il rischio di essere derubati è notevole. Nel mondo delle nanotecnologie i “disassemblatori” saranno comuni…
… I cannot simply put my friend's nanotech car or nanotech computer into a disk drive and burn a copy. I can, however, disassemble it. To do that, I use nanomachines that work like assemblers, but backward. Instead of starting with a description of where atoms are to go and putting them there, they start with an object - an automobile, say - and remove the atoms, one by one, keeping track of where they all were…
Soluzione 1:
… One approach to dealing with the problem of copying is an old legal technology, copyright… the solution may break down if instead of selling the car the pirate sells the design toindividual consumers, each with his own army of assemblers ready to go to work…
Soluzione 2:
… One possibility is tie-ins with other goods or services that cannot be produced so cheaply - land, say, or backrubs… the melodious voice telling you everything you didn't want to know about the lovely housing development completed last week, designed for people just like you. On further investigation,  you discover that turning off the advertising is not an option… you cast your mind back to the early years of the Internet, thirty or forty years ago, and the solution found by web sites to the problem of paying their bills…
Soluzione 3:
… Another possibility is a customized car. What you download, this time after paying for it, is a very special car indeed, one of a kind... But if you disassemble it and make lots of copies, they will not be very useful to anyone but you… This again is an old solution... all it requires is a CPU with its own serial number... it is possible to produce a program that will only run on one machine…
Soluzione 4:
… A third possibility for producing nanotech designs is open source: a network of individuals cooperating to produce and improve designs, motivated by some combination of status, desire for the final product, and whatever else motivated the creators of Linux, Sendmail, and Apache…
I software hanno un altro piccolo/grande problema: i virus
… Now consider a replicator designed to build copies of itself, which...in a startlingly short time, it could convert everything from the dirt up into copies of itself, leaving only whatever elements happen to be in excess supply…
Due possibili precauzioni:
… One precaution you could apply to assemblers as well as other replicators tors is to design them to require some input, whether matter or energy, not available in the natural environment… Another is to give them a limited lifetime
Le soluzioni proposte a questi problemi richiedono in molti casi un monopolista benevolente, ipotesi alquanto forte. Lasciando cadere questa ipotesi lo scenario diventa non meno plumbeo:
… One organization makes the breakthrough. Very shortly, after about forty doublings, it has a trillion assemblers. It sets them to work building what it has already designed. A week later it rules the world. One of its first acts is to forbid anyone else from doing research in nanotechnology... The result would be a world government with very nearly unlimited power
Scartiamo l’idea del dittatore globale e poniamo che esistano più governi indipendenti. I rischi non diminuiscono
… one possibility is that everyone treats nanotech as a government monopoly, with the products but not the technology made available to the general public...The problem with this solution is that it looks very much like a case of setting the fox to guard the hen house…
A questo punto essere d’aiuto un parallelo tra virus di internet e nanotecnologie distruttive…
… designer plagues will exist for much the same reasons that computer viruses now exist. Some will come into existence the way the original Internet worm did, the work of someone very clever, with no bad intent, who makes one mistake too many. Some will be designed to do mischief and turn out to do more mischief than intended. And a few will be deliberately created as instruments of apocalypse by people who for one reason or another like the idea…
Ma questo paragone è rassicurante
… With enough cell repair machines on duty, designer plagues may not be a problem. Human beings want to live and will pay for the privilege. The resources that will go into designing ing protections against threats, nanotechnological or otherwise, will be enormously... The only serious threat will be from organizations tions willing and able to spend billions of dollars creating really first-rate molecular killers…
Chiudo con la domanda decisiva: meglio un assetto centralizzato o decentralizzato?…
… in dealing with nanotechnology, we are faced with a choice between centralized solutions - in the limit, a world government with a nanotech monopoly – and decentralized solutions. As a general rule I much prefer fer the latter. But a technology that raises the possibility of a talented teenager producing the end of the world in his basement makes the case for centralized regulation…
Tuttavia, una ragione per il decentramento è ben illustrata bene da un’analogia:
… Smallpox. the only remaining strains of the virus were held by U.S. and Russian government laboratories. Because it had been eliminated, and because public health is a field dominated by governments, smallpox vaccination had been eliminated too... If a terrorist had gotten a sample of the virus... he could have used it to kill hundred of millions, perhaps more than a billion, people. That risk existed because the technologies to protect against replicators - that particular class of replicators - had been under centralized control. The center had decided that the problem was solved…
asphyxia-4