Why does life exist?
Popular hypotheses credit a primordial soup, a bolt of lightning and a colossal stroke of luck. But if a provocative new theory is correct, luck may have little to do with it. Instead, according to the physicist proposing the idea, the origin and subsequent evolution of life follow from the fundamental laws of nature and “should be as unsurprising as rocks rolling downhill.”
From the standpoint of physics, there is one essential difference between living things and inanimate clumps of carbon atoms: The former tend to be much better at capturing energy from their environment and dissipating that energy as heat. [Physicist] Jeremy England [...] has derived a mathematical formula that he believes explains this capacity. The formula, based on established physics, indicates that when a group of atoms is driven by an external source of energy (like the sun or chemical fuel) and surrounded by a heat bath (like the ocean or atmosphere), it will often gradually restructure itself in order to dissipate increasingly more energy. This could mean that under certain conditions, matter inexorably acquires the key physical attribute associated with life.
In the final years of the twentieth century, émigrés from mechanical and electrical engineering and computer science resolved that if th aim of biology was to understand life, then making life would yield better theories than would experimentation. Many of these researchers clustered at the Massachusetts Institute of Technology (MIT) beginning in 2003. Naming themselves synthetic biologists, they advocate not experiment but manufacture, not reduction but construction, not analysis but synthesis.
Armed with biotechnology techniques—notably, faster and cheaper methods of DNA sequencing and synthesis—this new breed of life scientists treats biological media as a substrate for manufacture, raw material that can be manipulated using engineering principles borrowed from their various home disciplines. Sequencing and synthesis allow synthetic biologists to traffic between physical molecules of nucleic acid (DNA and RNA) and dematerialized genetic sequences scrolling across computer screens. Sequencing means “reading” the strings of four nucleotide bases whose sequence constitutes DNA and RNA to compose a digital genetic “code” made up entirely of letters that stand in for the molecule (A for the nucleotide adenine, C for cytosine, G for guanine, T for thymine). Synthesis does the reverse: using elaborate genomic techniques, researchers can physically build material nucleic acid macromolecules to order on the basis of desired genetic codes.
Artificial Life is a field largely dedicated to the computer simulation—and, some would ambitiously add, synthesis in real and virtual space—of biological systems. It emerged in the late 1980s, out of interdisciplinary conversations among biologists, computer scientists, physicists, and other scientists. Artificial Life researchers envision their project as a reinvigorated theoretical biology and as an initially more modest but eventually more ambitious enterprise than Artificial Intelligence. Whereas Artificial Intelligence attempted to model the mind, Artificial Life workers hope to simulate the life processes that support the development and evolution of such things as minds. They plan to capture on computers (or, sometimes, in autonomous robots) the formal properties of organisms, populations, and ecosystems.
[Microbiologist Ed] DeLong informs his audience that life on Earth likely originated in swarming seawater, descending perhaps from a crew of microbes named the Archaea, or “ancient ones,” the famous of which reside at high-pressure, high-temperature, sulfur-spitting volcanic vents on the seafloor. These extraordinary organisms, DeLong says, might reveal the upper temperature limits of life and even suggest the outlines of life forms on lightless alien worlds, like Jupiter's satellite Europa, which may host hydrothermal activity. Microbial extremophiles—lovers of extremes—are ubiquitous on Earth, integral to the maintenance of this ocean planet.
The new astrobiology spends much of its time not in wet-labs experimenting with extraterrestrial analogues but in looking to other planets for what researchers call “the signature of life,” or often simply a “biosignature,” which is defined as “any measurable property of a planetary object, its atmosphere, its oceans, its geologic formations, or its samples that suggests that life was or is present. A short definition is a ‘fingerprint of life.’” A founding challenge presents itself here, according to astrobiologist David Des Marais, which is that researchers face the difficulty that “our definitions are based upon life on Earth” and that, “accordingly, we must distinguish between attributes of life that are truly universal versus those that solely reflect the particular history of our biosphere.” This is no simple task, because knowing what is universal is precisely what is to be discovered. Astrobiologists seek to discern the signature of life through examinations of, for instance, chemical assays of extraterrestrial rocks or spectral analyses of distant planets and then “infer from the biosignatures that life is or was present.” Such a search for signs of life from or in the sky is kin, of course, to the practices of SETI, the Search for Extraterrestrial Intelligence, though there are important mutations, too, most of which involve the retreat from the category of “intelligence” to a substrate called “life.”
In the early twentieth century, the life philosophy of Henri Bergson summoned the élan vital, or vital force, as the source of creative evolution. Bergson also appealed to intuition, which focused on experience rather than discursive thought and scientific cognition. Particularly influential for the literary and political Négritude movement of the 1930s, which opposed French colonialism, Bergson's life philosophy formed an appealing alternative to Western modernity, decried as "mechanical," and set the stage for later developments in postcolonial theory and vitalist discourse.
Revisiting narratives on life that were produced in this age of machinery and war, Donna V. Jones shows how Bergson, Nietzsche, and the poets Leopold Senghor and Aimé Césaire fashioned the concept of life into a central aesthetic and metaphysical category while also implicating it in discourses on race and nation. Jones argues that twentieth-century vitalism cannot be understood separately from these racial and anti-Semitic discussions. She also shows that some dominant models of emancipation within black thought become intelligible only when in dialogue with the vitalist tradition.