Templeton-Cambridge Journalism Fellowships in Science & Religion

Craig Venter and the Nature of Life

The world has its first synthetic cell, and the question 'what is life?' is more relevant than ever.

by Peter McKnight

Craig Venter may not be a god, but when he makes an announcement, the world shakes.

In 2000, the "dazzling showman of science," as he has been called, announced, together with U.S. National Institutes of Health scientist Francis Collins, a draft mapping of the human genome. So momentous was this announcement that not one but two world leaders -the U.S.'s Bill Clinton and the U.K.'s Tony Blair -felt the need to participate.

Now a decade later, Venter has done it again with the announcement that scientists at the J. Craig Venter Institute have created the world's first synthetic cell. This announcement also caught the ear of world leaders, as President Barack Obama fired off a missive to the Presidential Commission for the Study of Bioethical Issues, giving it six months to prepare a report on the promises and perils of synthetic biology.

Environmental groups were also quick to respond to the announcement, with some calling for a moratorium on such research, and other suggesting some form of regulation is in order.

And in response to the news that Venter "created" a synthetic cell, officials with the Catholic Church warned scientists not to forget that "there is only one creator: God."

Many of the concerns expressed are not unreasonable, though they aren't without hyperbole either. To see this, let's review what Venter actually did.

Venter's team of 25 scientists mapped the genome of a bacterial cell on a computer, modified it, broke it into 1,100 pieces and synthesized the pieces using four chemicals. They then assembled the genome fragments, and transplanted the complete genome into a cell that had had its genome removed. The synthetic genome was then "booted up" and the new "synthetic" cell began self-replicating.

Naturally, Venter emphasizes the promise of such research: The U.S. National Institutes of Health have provided him with funding for work that could lead to rapid development of flu vaccines, and Exxon has promised funding to create bacteria that can produce biofuels from algae. Beyond that, it might be possible to create bacteria that can aid in cleaning up oil spills, something that looms large in the American consciousness at present.

But just as advocates emphasize the promise of synthetic biology, critics highlight safety and security concerns. There is always the fear that a laboratory-created pathogen could escape the lab, and wreak havoc on the public and the environment. This doesn't have to occur by accident: Critics note that bioterrorists could synthesize their own pathogenic bacteria and hold the world hostage, if there is any world left.

That's a little dramatic, of course, but synthetic biology's potential threat to our safety and security is worthy of consideration. Curiously, though, the public doesn't seem particularly concerned, possibly because they don't see the potential threats as appreciably different from those presented by genetic engineering, which has already be the subject of intense debate, and more than a few sci-fi novels.

What has piqued public interest, though, is the suggestion that synthetic biology amounts to playing God. This was, of course, a charge also levelled at genetic engineering, and at virtually every new technology. But there seems to be something special about synthetic biology, since all this talk about creating a synthetic cell led some people to question whether Venter created life.

Anticipating such concerns, many scientists, including Venter himself, were quick to stress that he didn't create life, with Venter telling New Scientist, "We've created the first synthetic cell. We definitely have not created life from scratch because we used a recipient cell to boot up the synthetic chromosome."

What is life? Curious as it may sound, Venter doesn't

answer that question, and neither does anyone else. For millennia scientists and philosophers have attempted an answer, but it has proven elusive, partly because it is as much a

philosophical question as a scientific one.

Venter seems to be saying here that since the cell he used already amounted to "life," he wasn't doing God's work, or even Victor Frankenstein's. Fair enough, but that answer leads to another question -the primary question raised by Venter's work -- namely, "What is life?"

Curious as it may sound, Venter doesn't answer that question, and neither does anyone else. For millennia scientists and philosophers have attempted an answer, but it has proven elusive, partly because it is as much a philosophical question as a scientific one.

Early theorists suggested that living things possess an immaterial something that non-livings things don't. In ancient Greece, that thing was called a soul - psyche, or anima in Latin -- and we see this influence in our language today as we often speak of "animating" something as a metaphor for bringing it to life.

The rise of vitalism in the early modern period is another instance of this approach, as scientists suggested that organic matter possesses a "vital force" which is absent in inorganic matter. Various scientific discoveries led to the demise of this theory, though it still informs pseudo-sciences like naturopathy and homoeopathy.

After the demise of the magical theory of vitalism, scientists searched for a scientific definition of life based on its observable properties. And if the number of definitions promulgated is any indication, they were wildly successful. In 1970, astronomer Carl Sagan outlined five prominent definitions -the physiological, metabolic, biochemical, genetic and thermodynamic -and since, then, we've been inundated with literally hundreds more.

But of course the proliferation of definitions is not evidence of success; rather, it is indicative of failure. Every definition is beset by counter examples, which naturally lead to the development of other definitions.

Consider, for example, the metabolic definition, which is still popular among biologists. According to this definition, life is that which is capable of, among other things, converting energy to move and grow. The trouble with this definition is that it would include fire, which means fire would qualify as a living thing.

All the other definitions of life similarly include as living things that clearly aren't, or exclude things that are clearly alive. Suffice it to say, then, that no definition seems to work -they're either too broad or too narrow.

So how do we solve this problem of the definition of life? According to Carol Cleland, a philosopher at the University of Colorado and member of NASA's Astrobiology Institute, there's an easy way to do so -just stop looking for a definition.

This doesn't, of course, mean that we ought to give up. Rather, Cleland, whose ideas on this matter have received considerable press thanks to the work of Astrobiology Magazine's Leslie Mullen and science writer Carl Zimmer, suggests that we search for a theory of life, rather a definition of it.

As she explains in Defining Life, a paper co-written with astronomer Christopher Chyba, "Definitions specify the meanings of terms by dissecting concepts we already possess." For example, the definition of a "bachelor" as "an unmarried man" is unproblematic because we already possess the concepts of "unmarried" and "man."

But since life appears to be a natural category rather than a socially constructed one like bachelors, definitions won't do the job. We don't yet know what the essence of life is, and hence defining life -playing with words, if you will -won't lead us to discovering it.

In an interview in Astrobiology Magazine, Cleland likens our current conundrum to that of medieval alchemists who tried to define water based on its sensible properties: "The medieval alchemists classified many different kinds of substances as water, including nitric acid (which was called aqua fortis). They did this because nitric acid exhibited many of the sensible properties of water, and perhaps most importantly, it was a good solvent."

In other words, the medieval definition of water, focusing as it did on sensible properties, led to the inclusion of things that are most certainly not water. And just as with our definition of life, no new definition of water could ever solve this problem of including the wrong things (or excluding the right ones.)

Indeed, the only thing that could, and did, solve the problem was the development of the molecular theory of water -water is H2O. Since this theory informs us of the essence of water, it serves to clarify any ambiguities -we can identify water in any state anywhere on Earth, or indeed, in the universe, and we can exclude substances with similar or identical sensible properties.

Similarly, if we truly want to understand what life is, Cleland argues that we must not merely list its properties, but rather develop a theory of life similar to the theory of water. This is no easy undertaking to be sure, but Cleland and Chyba suggests two routes that might help get us there.

In Defining Life they state: "It is hard to imagine what could better help us to understand the nature of life than the synthesis of candidate living systems in the laboratory or the discovery of independent extraterrestrial biologies."

And this brings us back to Craig Venter.

The creations of synthetic biology -and the discovery of extraterrestrial life -could allow us to consider life that is completely different from that which occurs naturally on Earth.

And in considering such life, scientists might well discover what is truly essential to life -the essence of life -rather than merely cataloguing the sensible properties of living things.

Upon announcing his creation of a synthetic cell, Venter stated that his work represented a philosophical advance as a much as a scientific one.

And if Cleland and Chyba are right, then so is Venter: For while his work may be only a small step in the science of creating life, it could represent a giant leap toward a philosophical understanding of what life really is.