Leia este artigo intrigante de Susan Blackmore sobre o terceiro replicador evolutivo.
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Evolution's third replicator: Genes, memes, and now what?
31 July 2009 by Susan Blackmore
WE HUMANS have let loose something extraordinary on our planet - a third replicator - the consequences of which are unpredictable and possibly dangerous.
What do I mean by "third replicator"? The first replicator was the gene - the basis of biological evolution. The second was memes - the basis of cultural evolution. I believe that what we are now seeing, in a vast technological explosion, is the birth of a third evolutionary process. We are Earth's Pandoran species, yet we are blissfully oblivious to what we have let out of the box.
This might sound apocalyptic, but it is how the world looks when we realise that Darwin's principle of evolution by natural selection need not apply just to biology. Given some kind of copying machinery that makes lots of slightly different copies of the same information, and given that only a few of those copies survive to be copied again, an evolutionary process must occur and design will appear out of destruction. You might call it "design by death" since clever designs thrive because of the many failures that don't.
The information that is copied, varied and selected is called the replicator, and the process is well understood when applied to biology. Genes are copied, mutated and selected over and over again. Assemblages of genes are used to build vehicles that carry them around, protect them and propagate them. These vehicles - the lumbering robots, as Richard Dawkins calls them - are animals and plants, the prolific and exquisitely designed products of the first replicator.
About 4 billion years after the appearance of the first replicator, something extraordinary happened. Members of one species of lumbering robot began to imitate one another. Imitation is a kind of copying, and so a new evolutionary process was born. Instead of cellular chemistry copying the order of bases on DNA, a sociable species of bipedal ape began to use its big brain to copy gestures, sounds and other behaviours. This copying might not have been very accurate, but it was enough to start a new evolutionary process. Dawkins called the new replicators "memes". A living creature, once just a vehicle of the first replicator, was now the copying machinery for the next.
The idea of memes as a cultural analogue of genes has been much maligned, and most biologists still reject it. Yet memetics has much to offer in explaining human nature. According to meme theory, humans are radically different from all other species because we alone are meme machines. Human intelligence is not just a bit more or a bit better than other kinds of intelligence, it is something completely different, based on a new evolutionary process and a new kind of information.
The main difference between conventional theories and memetics is this: most biologists assume that culture and language evolved because they helped humans survive and pass on their genes, and that genes retain ultimate control. Memetics challenges that assumption. Although the capacity for imitation must once have been adaptive for the apes who started it, evolution has no foresight and could not have predicted the consequences of letting loose a new evolutionary process. Nor could it have retained control of memes once they began evolving in their own right.
So memes began to proliferate. What began as an adaptation soon became like a parasite - a new evolving entity that changed the apes and their world forever. Once memes were proliferating, individuals benefited from copying the latest and most successful ones, and then passed on any genes that helped them do so. This "memetic drive" forced their brains to get bigger and bigger, and to become adept at copying the most successful memes, eventually leading to language, art, music, ritual and religion - the successful designs of human culture.
This process was dangerous. Small brains are much more efficient if you don't have to copy anything, but once memes are around you cannot survive unless you do. So brains had to get bigger, and big brains are costly to produce, dangerous to give birth to and expensive to run.
There is also danger in what is copied. If you start copying anything at all then you might copy dangerous memes, like throwing yourself off a cliff or using up all your resources in pointless rituals. This creates an arms race between two selfish replicators - memes benefiting from brains that copy anything and everything; genes benefiting from brains that are smaller, more efficient and highly selective.
Either of these dangers might have finished our ancestors off, but they pulled through. The result was a compromise, with human brains being just about as big as our bodies could stand, and yet selective enough to avoid copying lethal memes. In the same way that parasites tend to co-evolve with their hosts to become less lethal, so memes co-evolved with us. Languages, religions, skills and fashions that began as parasites turned into symbionts. Not only do we get along with our memes now, we could not live without them.
There was also a cost to the rest of life on Earth. Wherever they went humans took memes with them, spreading agriculture and changing the landscape, obliterating some species, domesticating others and changing whole ecosystems. Then, much more recently, they began to build radically new kinds of technology, and the changes they effected dwarfed anything that had gone before. Was this just more of the same or something new?
In all my previous work in memetics I have used the term "meme" to apply to any information that is copied between people, including stories in books, ideas embodied in new technology, websites and so on. The reason was that there seemed no way of distinguishing between "natural" human memes, such as spoken words, habits, fashions, art and religions, and what we might call "artificial" memes, such as websites and high-tech goods. So on the grounds that a false distinction is worse than none I stuck to the term "meme". Yet an email encrypted in digital code, broken into tiny packets and beamed around the planet does seem qualitatively different from someone shaking hands and saying "Hi". Could there be a fundamental principle lurking here? If we ask what made memes different from genes, would that help us decide what would make a new replicator different from memes?
Putting it that way makes the answer easier to see. Memes are a new kind of information - behaviours rather than DNA - copied by a new kind of machinery - brains rather than chemicals inside cells. This is a new evolutionary process because all of the three critical stages - copying, varying and selection - are done by those brains. So does the same apply to new technology?
There is a new kind of information: electronically processed binary information rather than memes. There is also a new kind of copying machinery: computers and servers rather than brains. But are all three critical stages carried out by that machinery?
We're close. We may even be right on the cusp. Think of programs that write original poetry or cobble together new student essays, or programs that store information about your shopping preferences and suggest books or clothes you might like next. They may be limited in scope, dependent on human input and send their output to human brains, but they copy, select and recombine the information they handle.
Machines now copy information to other machines without human intervention
Or think of Google. It copies information, selects what it needs and puts the selections together in new variations - that's all three. The temptation is to think that since we designed search engines and other technologies for our own use they must remain subservient to us. But if a new replicator is involved we must think again. Search results go not only to screens for people to look at, but to other programs, commercial applications and even viruses - that's machines copying information to other machines without the intervention of a human brain. From there, we should expect the system to grow rapidly beyond our control and for our role in it to change. We should also expect design to appear spontaneously, and it does. Much of the content on the web is now designed automatically by machines rather than people.
Burneverything
The temptation is to think that technology we designed must remain subservient to us - but think again
Memes work differently from genes, and digital information works differently from memes, but some general principles apply to them all. The accelerating expansion, the increasing complexity, and the improving interconnectivity of all three are signs that the same fundamental design process is driving them all. Road networks look like vascular systems, and both look like computer networks, because interconnected systems outcompete isolated systems. The internet connects billions of computers in trillions of ways, just as a human brain connects billions of neurons in trillions of ways. Their uncanny resemblance is because they are doing a similar job.
So where do we go from here? We humans were vehicles for the first replicator and copying machinery for the second. What will we be for the third? For now we seem to have handed over most of the storage and copying duties to our new machines, but we still do much of the selection, which is why the web is so full of sex, drugs, food, music and entertainment. But the balance is shifting.
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