In looking through oklo’s activity logs, it is evident that many of the visitors are not from the audience that I have in mind as I write the posts. The site is continually accessed from every corner of the planet by robots, harvesters, spamdexing scripts, and viral entities that attempt to lodge links into the blog.

A common strategy consists of attempts to ingratiate with generically vague comments of praise:

The Turing test was envisioned as a text-only conversation with a machine. The machine passes the test if it can’t be distinguished from a real person. In Alan Turning’s Computing Machinery and Intelligence, he asks, “Are there imaginable digital computers which could do well in the imitation game?”

For now, the general consensus seems to be no. Machines can’t consistently pass the test (and the test itself seems increasingly dated), but their moment is approaching fast. Judith Newman’s recent NYT article about interaction with the iPhone’s Siri telegraphs the stirrings of the current zeitgeist.

The economics of comment spam must be relatively minor. Were serious money was at stake, a Nice Post! robot armed with state-of-the-art-2015 natural language processing skills and tuned to the universe of text strings and facts could almost certainly pull the wool over my eyes.

In early 2001, I was working at NASA Ames Research Center. The first Internet Bubble hadn’t quite ended. Highway 101 was a near-continual traffic jam. Narrow billboard trucks advertising this or that dot com were still cycling aimlessly up and down the Peninsula. We had just published our plan to move the Earth in response to the gradually brightening Sun.

I got an e-mail with a stanford.edu address from someone named John McCarthy, who asked if he could come to NASA Ames to talk with us about astronomical engineering. This was before the Wikipedia, and for me, at least, before the ingrained reflex to turn to the web for information about someone one doesn’t know. I just wrote back, “Sure!”

I recall McCarthy in person as a rather singular character, with a bushy white beard surrounding thick black glasses. He had a rattletrap car with a bulky computer-like device somehow attached next to the steering wheel. My co-author, Don Korycansky, was there. I remember that the conversation was completely focused on the details of the orbits and the energy budgets that would be required. We didn’t engage in any of the far-out speculations or wide-eyed ramifications that thrust us, as a result of my ill-advised conversation with a reporter a few weeks later, into a terrifying worldwide media farce.

Only later did I realize that John McCarthy was one of the founding giants of computer science. He coined the term Artificial Intelligence, invented Lisp, and was famous for his Usenet .sig, “He who refuses to do arithmetic is doomed to talk nonsense.”

McCarthy’s Progress and Sustainability web pages (online at http://www-formal.stanford.edu/jmc/progress/index.html) are dedicated to the thesis of optimism — that human progress is desirable and sustainable. He wrote, “There are no apparent obstacles even to billion year sustainability.” In essence, the argument is that the Anthropocene epoch, which began at 05:29:21 MWT on July 16, 1945, will stretch to become an eon on par in duration with the Archean or the Proterozoic.

Optimistic is definitely the operative word. It’s also possible that the computational innovations that McCarthy had a hand in ushering in will consign the Anthropocene epoch to be the shortest — rather than one of the longest — periods in Earth’s geological history. Hazarding a guess, the Anthropocene might end not with the bang with which it began, but rather with the seemingly far more mundane moment when it is no longer possible to draw a distinction between the real visitors and the machine visitors to a web site.

In writing about the rise of the data centers earlier this year, I suggested the “oklo” as the cgs unit for one artificial bit operation per gram per second. That post caught the eye of the editor at Nautilus Magazine, who commissioned a longer-form article and a series of short interviews, which are on line here.

In writing the Nautilus article, it occurred to me that the qualifier “artificial” is just that: artificial. A bit operation in the service of computation should stand on its own, without precondition, and indeed, the very word oklo serves to reinforce the lack of any need to draw a distinction. The Oklo fossil reactors operated autonomously, without engineering or direction more than two billion years ago. In so doing, they blurred snap-judgment distinctions between the natural and the artificial.

Several years ago, Geoff Manaugh wrote thoughtfully about the Oklo reactors, drawing a startling connection to a passage in the second of William S. Burroughs’s cut-up novels:

I’m reminded again here of William Burroughs’s extraordinary and haunting suggestion, from his novel The Ticket That Exploded, that, beneath the surface of the earth, there is “a vast mineral consciousness near absolute zero thinking in slow formations of crystal.” Here, though, it is a mineral seam, or ribbon of heavy metal—a riff of uranium—that stirs itself awake in a regularized cycle of radiative insomnia that disguises itself as a planet. Brainrock.

Revising the definition,

1 oklo = 1 bit operation per gram of system mass per second,

brings the information processing done by life into consideration. Our planet has been heavily devoted to computation not just for the past few years, but for the past few billion years. Earth’s biosphere, when considered as a whole, constitutes a global, self-contained infrastructure for copying the digital information encoded in strands of DNA. Every time a cell divides, roughly a billion base pairs are copied, with each molecular transcription entailing the equivalent of ~10 bit operations. Using the rule of thumb that the mass of a cell is a nanogram, and an estimate that the Earth’s yearly wet biomass production is 10¹⁸ grams, this implies a biological computation of 3×10²⁹ bit operations per second. Earth, then, runs at 50 oklo.

Using the Landauer limit, Emin=kTln2, for the minimum energy required to carry out a bit operation, the smallest amount of power required to produce 50 oklo at T=300K is ~1 GW. From an efficiency standpoint, DNA replication by the whole-Earth computer runs at about a hundred millionth of the theoretical efficiency, given the flux of energy from the Sun. The Earth and its film of cells does lots of stuff in order to support the copying of base pairs, with the net result being ~200,000 bit operations per erg of sunlight globally received.

Viewed in this somewhat autistic light, Earth is about 10x more efficient that the Tianhe-2 supercomputer, which draws 17,808KW to run at 33.8 Petaflops.