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Taxi from Another Planet, by Charles S. Cockell

I said it in my review back in May of David George Haskell’s Sounds Wild and Broken: Sonic Marvels, Evolution's Creativity, and the Crisis of Sensory Extinction: “I already live on a knife-edge of awe, stunned disbelief and overwhelmed incomprehension when it comes to the natural world we inhabit.”

But I keep trying understand more, and so I turned to Taxi from Another Planet: Conversations with Drivers about Life in the Universe, by Charles S. Cockell. With this book, I go beyond “the natural world we inhabit” and journey into both the origins of life on Earth as well as the farthest reaches of the universe. And I make the trip by taxi!

Kudos to the author, who is a Very Serious Astrobiologist with the University of Edinburgh, and to Harvard University Press, a Very Serious Publisher, for presenting some Very Serious Science into such an entertaining and even whimsical package. It has become almost hackneyed for journalists to pay tribute to taxi drivers as sources of inspiration and information. The author of this book happily latches on to the tradition, initially inspired by a question posed by one particular driver in 2016:

Taxi drivers are linked into the collective mind of our civilization in a way few of us are. They feel the pulse of human thought...Unencumbered by a cartload of academic knowledge, technical detail, and the conservatism bred by uncertainty, taxi drivers have clear perspectives on the sorts of questions that most people find significant. Sometimes, they offer an entirely new point of view…. Name a single academic who would stand in front of 200 university students and ask, as though it were a profound question, whether there were alien taxi drivers. Yet here we were. 

And off we go in the first chapter of the book, examining various theories of whether life on Earth is unique, or whether it is just one node of a universal pattern that would be replicated countless times, with lifeforms dropping the flag in their taxis as they ferry others around on countless planets throughout the universe. What exactly is it that triggers, as he calls it, the “transition from mere chemistry to biology.”

Whenever I read about this subject, I’m always left with the same feeling I have when reading a novel with huge holes in the plot. Cockrell admits that there is still much we don’t understand, but runs through the science of the CHNOPS elements—carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur--churned out by stars as the universe was formed; the energy sources that might allow those elements to react with other elements; how those reactions could have led to self-replicating cells; how those calls might have evolved to more complex organisms. We know a lot about each stage and the science behind it, and Cockrell explains it very well, but there is always that bit of a loss of explanation as to how exactly things progressed from one stage to another. And so there remains the question: are these laws of physics, chemistry and biology able to kick in and lead to an infinite number of taxi drivers in infinite different circumstances across the universe, or is there something unique about Earth that enabled nature to hack hack drivers?

The question as to whether life is inevitable everywhere is returned to later in the book, in a chapter entitled “How Did Life Begin.” Here we learn about phospholipids, molecules that have the peculiar ability to arrange themselves into a membrane, and thus bringing the possibility of organization an otherwise chaotic swirl of chemicals and chemical reactions. If, as is said, humans are in essence just walking bags of chemicals, there had to have been a point in which bags were created. And here we learn about the Murchison meteorite, which crashed into Australia in 1969. It turns out that within alien 4-billion-year-old relic of the universe were long chains of carboxylic molecules essential to life. But the spark of life needs more: it needs something to work as a catalyst, like strings of amino acid molecules called enzymes. It turns out the Murchison meteorite also contained some 70 types of amino acids. In short, this alien rock had within it the stuff of life. So maybe Earth isn’t so unique after all.

Will we ever be able to fully understand the progression from a swirling chaos of elements to me sitting here typing symbols on a computer? Still an open question.

The book is full of great questions, and a lot of well-explained answers as well. Each chapter is framed around a specific taxi ride, with the conversation with the driver serving as both catalyst and membrane for the information presented. A chapter on the potential outcomes of alien contact gives an amusing history of humankind's beliefs on the subject. Early on, there was an expectation that of course there would be life elsewhere. Metrodorus of Chios in ancient Greece wrote: “It would be strange if a single ear of corn grew in a large plain, or there was only one world in the infinite.” (There strikes me as something off about this quote, since corn as I understand it had its origin in pre-Columbian America and would not have been known to Metrodorus in 4 BCE; it must have been some other crop in the quote.) In 1584, a Dominican monk named Giordano Bruno wrote “For no reasonable mind can assume that heavenly bodies that may be far more magnificent than ours would not bear upon them creatures similar or even superior to those upon our human earth,” Bruno ended up being burned at the stake by the Inquisition. Montesquieu, noting an experiment in which a sheep’s tongue, when frozen, induced the tiny hairs presumed to be the producers of taste to retract. From this, he further surmised that cold inhibited creativity, and that beings on, say, Venus, closer to the sun and hotter, may have superior musical abilities.

We also ponder microbial life, which is vastly the most numerous on Earth, and our ethical responsibility to take extreme measures to not introduce them to other planets. We learn about the possibility of ghosts, what human colonization of Mars might be like, and how we might communicate with aliens. We learn the ins and outs of such questions as the possibilitty that we are inhabitants of an alien zoo. We discuss the philosophy of the meaning of life.

Politics enter the mix as well. Is it wasteful to spend money on space exploration? Will alien societies be tyrannical or freedom-loving? On that last question, the author is something of an expert: among his other books are Extra-Terrestrial Liberty an Enquiry Into the Nature and Causes of Tyrannical Government Beyond the Earth, and Human Governance Beyond Earth: Implications for Freedom, books that ponder the implications of societies in situations like interplanetary travel, in which isolation and lethal environments are at the forefront.

A fun book, and highly recommended.