On Intelligence, part one

The following is part of an essay I wrote back in 2000 or something, as part of a 600-level course in astronomy and exobiology. I'm not big on recycling old material, but I'm even less big on re-inventing the wheel, and there's material here I want to present before delving deeper into the topic of extra-terrestrial intelligence. I've edited it here to read a bit less like a post-grad paper, but I'm leaving the original content more or less intact. I'm going to present this here in installments, because the original essay is rather long. I probably won't disclaimer all of the later installments, or excerpts from other essays from that time, so let this disclaimer stand for all of them.

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The first obstacle in the path of finding extraterrestrial intelligence is to define
“intelligence”. Even when discussing terrestrial animals, the concept of “intelligence” is at best an abstraction. Some criteria for intelligence have been such things as total brain mass, brain-to-body-weight ratio, neocortex-to-bodyweight ratio, communications and behavior. Using these criteria, reasonable arguments may be made for the intellectual superiority of such creatures as humans and other apes, crows, cetaceans, mice, dogs, cats, bees and spiny anteaters. It is questionable whether humans possess the intellectual capacity to recognize intelligence in other species, or to meaningfully define intelligence
generally. From a purely evolutionary standpoint, every species which currently exists would be, by definition, equally “intelligent” for its evolutionary niche or it would have been out-competed by a more “intelligent” species.

However, for the purposes of the current search for extraterrestrial life, we can eliminate a great many of the abstract considerations of what constitutes actual intelligence, and simply focus on the specific types of intelligence which might produce EM transmissions. As EM energy is the first (and currently only) possible means for humans to communicate beyond this planet and beyond the solar system, we are limited to this spectrum, and any species communicating by other than EM means are self-eliminated from the search. Within the EM spectrum, we can narrow our definition of “intelligence” to mean the type of intelligence which can produce narrowband EM transmissions which are pulsed into a pattern which is readily identifiable as non-random. This effectively limits the search for extraterrestrial intelligence to such intelligences as humans, which are now able to produce such EM transmissions artificially, and fireflies, which are capable of producing such transmissions biologically. There is no reason to postulate the greater
likelihood of biological or artificial ability to transmit in the EM spectrum, nor is there any reason to assume that either would necessarily be more likely to possess a type of intelligence similar to our own. However, it is
possible that a species which developed artificial means of transmitting and receiving EM energy would have undergone a greater number of analogous steps in their intellectual evolution to our own, than a species which had evolved a biological means of transmitting and receiving in this spectrum. For this reason, we will focus our search on those species which have developed EM technology independent of any biological mechanism for producing this, whether or not we would be able to discern the difference from Earth-based telescopes.

We have not yet discovered another world within our own solar system which
conclusively harbors life, although Europa is a prime candidate. As we have observed no evolutionary models other than our own, we can, at this point, only extrapolate from our own evolution what course the evolution of intelligence might take on another world. The steps in our own evolution which might reasonably be expected to have extraterrestrial analogues leading to the development of EM technology are as follows:

Impeti 1: Organic chemicals to prokaryotic life
Evolutionary Impeti 2: Prokaryotic life to eukaryotic life
Evolutionary Impeti 3: Cambrian explosion (2011 note: I was unaware of the Ediacaran Biota when I wrote this, which fundamentally changes this part of the equation)
Evolutionary Impeti 4: Prehensility
Evolutionary Impeti 5: Technology
Evolutionary Impeti 6: Intelligence (development of EM technology)

By this definition, homo sapiens became an intelligent species in September of 1895 ev, when Guglielmo Marconi became the first intelligent mammal on earth. Now, a little more than a century since this achievement, humans are able to demonstrate their intelligence every time they place a call on a cellular telephone.
Prehensility is of course critical, as species which might otherwise be construed as
“intelligent” which have no physical means of creating technology (such as some
cetaceans) tend not to build artifacts capable of transmitting in the EM spectrum. It is over-simplifying the situation, however, to assume that an orderly progression from the digging-stick to the cellular telephone (or radio telescope) is inevitable for any prehensile and technologically inclined species.
Even species which happen to develop EM technology may not utilize it for
communications, either because they have methods of communication which are superior
to EM, or simply because it does not occur to them to do so. For example, many human
cultures have, independently of one another, developed both cups and strings; however the number of human cultures who have adapted these technologies to create crude telephones out of them is significantly small. The analogy is not a bad one; SETI itself is rather like standing on an island with a cup-and-string telephone and sticking one cup to our ear and holding the other cup out to the sea, and hoping to hear people talking on some other island. And then shouting into one cup while holding the other cup out to the sea, hoping someone out there will hear us.