Daniel Oberhaus is a science and technology journalist who specializes in space travel and the future of energy. Currently staff writer for Wired, he recently wrote the introduction for da Silva, Burleigh and Obraczkahis’ academic tome of hard sci-fi inspiration, Delay and Disruption Tolerant Networks: Interplanetary and Earth-bound – Architecture, Protocols and Applications. His first monograph, Extraterrestrial Languages, provides an accessible overview of largely Western approaches to communicating with aliens. This informative short history of astrolinguistic imagination and experimentation discusses nineteenth and twentieth century speculations, inventions and attempts to capture the attention of any sharp-eyed or -eared alien cultures that may be out there.

The account is foregrounded in descriptions of nineteenth century European curiosity about extraterrestrial life before technologies for interstellar transmissions and space exploration were developed. This is exemplified in the number of plans for attracting attention from outer space using a range of methods that now seem hilariously crude: landscaping large-scale geometrical forms; digging enormous fire pits; using mirrors to burn shapes into Martian deserts; and arrays of electric lamps for signaling using Morse code style languages. The main body of the book however considers twentieth century alien contact attempts, at first termed CETI (communication with extraterrestrial intelligence), then renamed METI (messaging extraterrestrial intelligence). CETI and METI are offshoots of SETI, the global acronym for alien-hunting projects (the search for extraterrestrial intelligence).

The survey of twentieth century METI projects includes radio transmissions, laser beams, and probes carrying intergalactic missives in bottles. These transmit messages in various formats, from newly invented symbolic languages to bitmaps, each complete with opaque directions – the xenolinguistic construction and decoding equivalent of Ikea assembly instructions. A bitmap is a form of memory organization for storing digital images encoded as a spatially mapped array of data (bits). Messages consisting of strings of binary digits to reveal images were transmitted from Puerto Rico’s Arecibo telescope in 1974, and symbolic bitmap codes for decrypting physics communications broadcast from the Ukrainian Evpatoria telescope in 1999. In 2003, the Evpatoria telescope relayed binary code for aliens to build their own artificial intelligence (AI) chatbot Ella. Decryption instructions for these intergalactic dispatches were grounded in the assumption that mathematics is a universally understood language, even among extraterrestrial beings. We learn that the xenolanguage, Astroglossa, invented by British experimental zoologist Lancelot Hogben in 1952, was constructed with a numerically based radio lexicon and syntax. Dutch mathematician Hans Freudenthal’s cosmic symbolic language, Lincos, in 1960, was built up from basic numbers and symbolic logic. And mathematician Carl DeVito and linguist Richard Oehrle’s 1990 xeno-communication system was arithmetically-based. While these might appear to astronomers and mathematicians to be self-evidently decipherable forms of intelligence, how might they be translated or even noticed by nonhuman life-forms? As Oberhaus points out, the form and content of all these attempts are informed by the human broadcasting culture’s prevailing philosophies, linguistics, mathematics, science and art of their time, channeled through its most evolved technologies.

The book gently questions the universalist assumptions and anthropocentrism these messages are based on, but ambivalently chooses to follow AI pioneer Marvin Minsky’s 1985 hypothesis that any alien intelligence we contact will be a human-like intelligence. Oberhaus omits to mention, however, that Minsky himself frames this hypothesis as a weak argument, and his definition of intelligence is predicated on human intelligence (“If one can't say how their intelligence is similar, it makes no sense to use the same word”). Minsky’s article about alien intelligence really operates as a pretext to present his research for human intelligence-based AI. As Oberhaus recounts, Minsky suggested that even eight-limbed extraterrestrial beings may evolve comparable solutions to humans when faced with the same environmental constraints such as limited resources and time. Computer scientist Michael Arbib’s astrolinguistic thought experiment based on an eight-armed alien he calls an octoplus is a glaring omission that offers a different perspective, as are a number of the other essays published in the same 2013 volume, The History and Philosophy of Astrobiology: Perspectives on Extraterrestrial Life and the Human Mind. The range of cognitive zoological, xenolinguistic, and xenosemiotic approaches featured would add depth and weight to the argument Oberhaus appears to be trying to make about the species bias inherent to previous METI attempts.

While Minsky suggests it is likely that extraterrestrials have discovered similar efficient solutions to those humans have found (such as symbolic language), Arbib considers the implications of another species’ morphology on the development of its symbolic language. His essay applies neuroscientific theory to this distinct eight-limbed marine-dwelling sensorimotor system, which leads him to propose possibilities for very different, nonhuman symbolic languages and mathematics. Arbib suggests it is probable that octopus-like intelligence would produce concepts and syntax entirely different from human ones, formed through their embodied cognitive perceptions and relationship to their environment. Similarly, in Ted Chiang’s 1998 science fiction short, ‘Story of Your Life’, the language of the seven-limbed aliens is structured to reflect the way they perceptually inhabit the world, remembering the future as well as the past: their sentences are circular constructions, existing in space but not time. This cognitive linguistic viewpoint chimes with findings of the neuroimaging research Oberhaus cites, which demonstrates that language structures echo brain activity patterns, functioning as expressions of internal bodily processes.

The ‘Aliens on Earth’ chapter discusses interspecies communication as a model for alien messaging. For example, John Lilly’s famous dolphin experiments showed that dolphins were able to learn up to 50 words of human language, but no human was able to decipher any of the complex array of clicks and whistles that make up dolphin communication. His investigations raised questions about human capacity to recognize other forms of intelligence. Oberhaus strangely labels dolphin communication presymbolic, rather than the more obvious nonsymbolic, following a discussion about evolutionary convergence of human-like intelligence. This is highly contested theoretical territory. As Terrence Deacon explains in his 1997 The Symbolic Species, symbolic language has only occurred as one peculiar, if very successful, evolutionary niche on this planet, and has also been used as an example of extreme divergence in evolution.

Extraterrestrial Languages constitutes a concise introduction to the topic, condensing historical accounts and scientific thought on astrolinguistics into a clear and readable primer. The appendices usefully contain more detail about the workings of the xenolanguages described for more mathematically inclined and interested readers or those wishing to design and encode their own. One of the book’s stated aims are to focus on attempts to “eliminate species bias” in extraterrestrial communication efforts (p.167), which seem to be lacking in this respect so far. An extraterrestrial communications system that does not presume a human-like intelligence has yet to be developed. If aliens tried to contact us, would just we fail to notice, as occurs in Olaf Stapledon’s science-fictional account of an invasion of earth by microbial intelligences in Last and First Men (1930). Like most of the fascinating communiqués and systems it details, this could more accurately be described as a book about human solipsism than credible extraterrestrial languages. If this is how METI attempts really operate, they’re basically just combing outer space for other humans.