Signs of life

三月 30, 2007

Is the distinction between nature and culture false because nature evolved to interact in codes? Geoff Watts gets a primer in signals right down to the genetic level.

Semiotics is the study of signs. Biosemiotics is the application of semiotics to biology. No problem so far. But what exactly does it mean to talk of studying signs in biology? As meaning and interpretation are core elements of the semiotic project, this is surely a most pertinent question. Alas, the answers you get from biosemioticians themselves are - sometimes by their own admission - a sight less straightforward than the query eliciting them.

To transcend its origins as a method of scrutinising the products of culture, and then to penetrate science, semiotics has had some tough disciplinary boundaries to negotiate. The "signs" that constitute the raw material of semiotics are not only words but gestures, sounds, objects, images or anything that represents or stands for something else. Semiotics, which is not so much a discipline as a collection of analytic tools, has a following among theorists working in the arts, the media, linguistics, sociology, philosophy and a clutch of other branches of learning.

Whether the sign in question is part of an advertisement or a novel, a picture or a piece of music, the semiotician's underlying assumptions are broadly similar: that meaning is not a fixed inherent property of the sign, but something we read into it; that, unless we try actively to decode it, we may fail to understand the conscious or inadvertent intentions of its creator. Not all of what passes for objective reality can truly be considered as such. While some critics are dismissive of the semiotic approach, its relevance in principle when aiming to delve beneath the surface of a film, a party political broadcast or a poem is not too hard to discern.

But what does it means for biology? Jasper Hoffmeyer works at the University of Copenhagen's Institute of Molecular Biology. "The biosemiotic way of looking at things marks a break with the old division of the world into natural and cultural," he says. "The way it does this is by showing that the reality of signs is not exclusively of the human sphere. Signs grew in evolution. All living things can be understood as semiotic systems." The general argument is that biological entities do not interact like mechanical bodies, but rather as messages. And biological information, adds Hoffmeyer, is inseparable from its context; it has to be interpreted to achieve anything.

From the feathery display of a male peacock to the flower pattern that guides an insect towards its nectar, the natural world is self-evidently rich in signs through which animals and plants communicate. But biosemiotics goes deeper than this. Marcello Barbieri, professor of embryology of the University of Ferrara and editor of the recently published Introduction to Biosemiotics , is among those scientists who are applying this analysis at the level of cells and molecules. As he points out, Francis Crick and James Watson's revelations about DNA and the mechanism of heredity signalled the end of biology as a study dominated by descriptions of the energy flow within and between organisms.

The emphasis now is on information: how it is coded in the genes; how it is utilised to create and control living cells; how it is copied and passed to subsequent generations. Most biologists know little or nothing of semiotics, let alone its application to their discipline. Most would probably query what it has to offer. Don't ethologists, they would say, study the behaviour of animals, including the ways they communicate? And wasn't it molecular biology, not semiotics, that cracked the genetic code, that revealed how each amino acid of a protein chain is specified by a triplet of nucleotide molecules? True enough.

Biosemioticians respond in two ways. "Semiotics has the advantage of providing good tools, useful methodologies for studying these things," says Dario Martinelli, a lecturer at the University of Helsinki. He accepts the overlap between semiotics and ethology, but adds that both are enriched by their interaction. Taking the argument to the molecular level, Barbieri points out that, while the process of using one DNA molecule as the template on which to build another is an act of simple copying, the process of transcribing a DNA sequence to specify a protein is an altogether different act: one not of copying but of coding. The distinction is an important one, especially when considering the mechanism of evolution.

Some biosemioticians are reluctant to accept the conventional view of natural selection (DNA copying, but with errors that provide variant organisms of greater or lesser fitness) as the driver of evolutionary change. Barbieri accepts it, but finds it an insufficient account.

Explaining why, he compares the evolution of a species with the evolution of a language. Suppose the only way that languages could change was by copying with errors. "The Latin word ' pater ' becomes ' padre ' in Italian, 'father' in English, and so on. But this is looking only to see how information is conveyed in individual words." It takes no account of grammar, he adds, the collective rules of language.

Can you explain the evolution of a language by looking only at changes in the words and disregarding changes in grammatical rules? He thinks not. So too with biological evolution, a gap that biosemiotics is exploring and aims to fill. Unfortunately for Barbieri, Hoffmeyer and their colleagues, many biologists are indifferent to this gap and the attempt being made to plug it.

Even more problematic to conventional biology is that some biosemioticians seem to be openly vitalist. "This is not my position," Hoffmeyer says.

"This supposes that you have special forces that are unique to the life world as opposed to the physical world." He doesn't have "any such stupid ideas" and will countenance nothing that contradicts the laws of physics. But what this illustrates is the broad, if not bewildering, variety of views to be found in biosemiotics - some of which, to the outsider at any rate, smack of pure mysticism.

And biosemiotics does not do itself many favours by inventing new and sometimes unnecessary words, or using the same word to mean different things. And sometimes it seems to be redescribing the familiar for no obvious reason. Hoffmeyer has heard it all before. "It's a very familiar accusation because we are, of course, redescribing things, but with a purpose. Somehow we must put our theories in a different light, and you cannot do that without redescribing them," he says.

So, there you are: protein synthesis, whale song, man's relationship to the environment. It's all grist to the biosemiotic mill, which recognises no boundaries to its pursuit of signs and their meaning. Only one thing is beyond dispute. If biosemiotics is ever to engage with a wider audience, it will have to devise a more transparent form of discourse.

'SHOULDN'T WE LOOK AT HOW a WHALE MAKES ITS OWN MUSICAL SENSE OF SOUND?'

Typical of the geographic as well as disciplinary shifts that seem to characterise biosemiotics is Dario Martinelli. Originally a musicologist, he became interested in semiotics while at the University of Bologna. "I was always fascinated by the idea of combining music with something that goes beyond human culture," he says. He heard about the study of zoomusiciology and moved to the University of Helsinki to do a PhD. He now teaches there and has published Zoosemiotics: Proposals for a Handbook .

When I asked whether biosemiotic redescriptions of the world added anything, he chose a zoological example: music and whales, a topic on which he has written extensively.

"One way of approaching supposedly musical behaviour in animals is to use human criteria. The more that the animals' sounds resemble human music, the more we call them music. That's why we prefer nightingales or humpback whales to seagulls. But shouldn't we rather look at how a species is making its own musical sense out of sound? Shouldn't we rather try to get inside their minds? It is misleading to analyse the phenomenon from a purely human standpoint." In this instance, he argues, changing the way you describe a phenomenon could alter the way you investigate it.

But couldn't an orthodox ethologist take just such a point of view? He says some do, which is one reason why many people prefer to think of semiotics not as a separate discipline but as an approach to understanding the world.

Martinelli is critical of some of his peers who believe that biosemiotics will revolutionise everything in biology. "Some semioticians claim to have found the ultimate truth about things. I've always been against this. Also, biology is a natural science, while semiotics originated as a human study. We have an approach that is more philosophical and sometimes less empirical. This might clash with someone who is more oriented towards natural sciences."

NOT ALL DOWN TO DNA?

British-born Peter Harries-Jones is professor emeritus of anthropology at Toronto's York University, where he is writing his second book on the life of another anthropologist, Gregory Bateson. Bateson was a thinker and commentator much revered by the biosemiotic community. He believed there was more to evolution than conventional Darwinian theory would allow, a view shared by his biographer.

Development also poses problems, Harries-Jones says. In the transition from egg to fully formed organism, there has to be more involved than just the instructions from the genes. The Human Genome Project revealed that we have far fewer genes than originally imagined.

Although conventional biology has sought to account for the complexity of development by talking of some genes controlling other genes, it still has no firm explanation for the emerging complexity of the developing embryo.

Environmental factors, too, must play a part, maintains Harries-Jones. And he points to biology's increasing interest in epigenetics. This subject, which is defined as the study of heritable changes that happen without an alteration to the DNA sequences within the nucleus, is of great interest to developmental biologists.

Because it can suggest mechanisms by which gene activity might respond to the local environment, it has the potential to offer a more complete account of the process of development. More controversially, it also provides a mechanism for the inheritance of certain acquired characteristics.

This is the kind of signalling complexity on which semiotics thrives, and some biosemioticians have embraced it with enthusiasm.

Harries-Jones is more interested in the currently dire influence of our species on the planet. But he sees clear parallels between a mindset that is prepared to contemplate the subtlety of epigenetic influences and one that accepts the need to reinterpret radically the relationship of our fully formed selves to the environment.

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