Exploring Carl Sagan’s Cosmos

Exploring Carl Sagan’s Cosmos: Episode 11, “The Persistence of Memory”

The eleventh episode of Cosmos, “The Persistence of Memory,” moves from outer space to the interior of the mind, examining the mechanics of knowledge and intelligence. Sagan opens by discussing units of information, and then shifts to a simple thought experiment: what better way to consider the possibilities of alien intelligence than by considering the intelligences in our own oceans? This leads to an exploration of whales and whale communication—and that leads to how whales know what they know, as mammals like us: genes and brains. The rest of the episode explores the intricacies of these two containers of knowledge, and finally extends the conversation into the realm of knowledge humans store outside themselves: texts, libraries, etc.

“The Persistence of Memory” plays with juxtaposition in a way that never ceases to impress me; it’s got one of those circular narratives that we haven’t seen since the earliest episodes of the series. At the beginning of the segment on whales, it seems strange and unrelated to a discussion of bits of information. But after leaping gently from topic to topic, loosely connected, Sagan finally ends up in a place where it is all connected: as he says, we have gone “from genes, to brains, to books.” Beginning with whales allowed us a way to consider the possibilities of intelligence outside of the human, to create a not-entirely-human-centric narrative of intellect; we then close with extraterrestrial life, and how it might help us as a species to try and communicate on our own planet before we must communicate with intelligences from vastly different worlds. Without the whales at the beginning, that circularity wouldn’t function the way that it does, and the interconnectedness of life on this planet wouldn’t have been made so very clear.

“What an astonishing thing a book is. It’s a flat object made from a tree with flexible parts on which are imprinted lots of funny dark squiggles. But one glance at it and you’re inside the mind of another person, maybe somebody dead for thousands of years. Across the millennia an author is speaking clearly and silently inside your head directly to you. Writing is perhaps the greatest of human inventions, binding together people who never knew each other, citizens of distant epochs. Books break the shackles of time. A book is proof that humans are capable of working magic. This room is full of magic.”

Exploring Carl Sagan's Cosmos: Episode 11, "The Persistence of Memory"

It is probably not a surprise that this is my favorite episode of Cosmos. That’s mostly on the virtue of the last twenty minutes or so: the discussion of external knowledges—books, libraries, texts of all sorts, digital communications—is, for my vote, the most moving of all the scenes in the series. There’s a reason that my intro quote is an entire paragraph; there’s just nowhere to cut that that wouldn’t remove something vital and beautiful. I admit it, I cry on occasion when watching this section.

In particular, I am always silenced by the moment where Sagan discusses the limitations of the single human: a book a week for an adult lifetime is only a few thousand books. Measuring down a stack, Sagan notes: “In this library, that’s from about here… roughly to about here.” And that’s barely any books at all—only 1/10th of a percent or so of the total of books in the New York Public Library. He’s right when he follows up by saying, “the trick is to know which books to read, but they’re all here.” On the other hand, it doesn’t stop that moment from being at once stunning and devastating for me. From there, to there—that’s so little, in comparison to the wealth of information that’s out in the universe. (I often say, only half joking, that the one thing that bothers me about my own mortality is that I’m going to die with books unread that I wanted to read.)

Exploring Carl Sagan's Cosmos: Episode 11, "The Persistence of Memory"

It doesn’t stop there, either; I also love the continuing, global discussion of the wealth and wonder of books. Sagan, here, does acknowledge the international nature of technology and science: China invented paper, ink, and block printing and “backwards” Europe, as he says, took a much longer time to adopt it. He also notes that libraries contain the best minds “from the whole planet,” rather than merely those of the West. It’s a global perspective on the sharing of knowledge, and how we externalize and secure it so as not to lose it to the ravages of time. I’m also amused by the gesture at the end of the episode toward the future possibilities of the digital age—which we are now firmly ensconced in. And yes, it certainly has made a vast difference in the trade of knowledge and information; the NYPL is dwarfed by the interconnected, huge “libraries” of the digital sphere. This essay, this blog post that you are reading now, is one of those bunches of bits of text added to the vastness of human-produced knowledge, and doesn’t that feel odd to think about as the words appear on my screen, one after another? Sagan’s prediction was spot-on.

Of course, I’ve known other people who have different favorite scenes or most moving moments. Cosmos’s wide focus, and Sagan’s equally wide-ranging poetic enthusiasm, allows the series to speak to an array of people on their own particular topics of passion. (Feel free to share your own.) It just so happens that the bits about our brains and how fantastic they are, and our libraries and how fantastic they are, move the hell out of me. The whales are fascinating; genetic libraries are dense and intriguing and show how interconnected life on this planet is; but our brains and our externalized knowledges? That’s the stuff that gets me going, probably because it’s what I do with my life—or is that a chicken/egg proposition?

Exploring Carl Sagan's Cosmos: Episode 11, "The Persistence of Memory"

That other stuff is in the episode, though, and it’s worth mentioning. I particularly appreciate the intentional remove Sagan creates by treating our planet as if he was an alien: we’re a water world, so of course it would make sense to search our oceans for our life and intelligence. He keeps the proposition up for a long time, too—he makes it all the way to himself standing on a ship before we realign into a human point of view. As he discusses the beautiful undersea creatures that “flutter like waltzing orchids” and shows us clips of a clam swimming (something I find wonderfully absurd), I am consistently entranced. The world is a weird place, containing lots of weird things that are different from us, and yet ultimately similar.

The complexity of our genetic library, too, is illustrated with a useful metaphor—printed standard text. The gene library is made of DNA, as Sagan explains: a virus is like one page of a book; a bacterium is about 100 pages; an amoeba is like 80 volumes of 500 pages each; whales or human beings are over a thousand volumes. Just think about that size differential and complexity—it’s a great extended metaphor for explaining the content of DNA. Poetry strikes again in Cosmos to do the work a textbook couldn’t quite do, for a much wider audience.

In closing:

“Books are like seeds: they can lie dormant for centuries, but they may also produce flowers in the most unpromising soil.” And, if we want to hearken back to the Library of Alexandria: books are also “nourishment for the soul.”


Come back next week for episode 12, “Encyclopaedia Galactica.”

Brit Mandelo is a writer, critic, and editor whose primary fields of interest are speculative fiction and queer literature, especially when the two coincide. She can be found on Twitter or her website.


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