There are several aspects to John’s hypothesis, so it was quite a challenge to condense the argument into just three pages of the book (and even more of a challenge to use only simple words to describe some rather abstruse concepts; I lack Roberto Trotta‘s ability to illustrate rarefied ideas with monosyllables).
One aspect is relatively easy to describe and understand: John argues that advanced civilisations will collapse. Note that this is not collapse in the sense of Gibbon’s Decline and Fall! Rather, civilisations will develop in an inward direction rather than outward into space. Qualities that might be used to characterise civilisations – their use of space, time, energy, matter – will all exhibit an increase in density. In John’s words, civilisations will undergo STEM compression.
You can argue that STEM compression is happening to our own civilisation. Let’s consider just one of those four STEM dimensions. In the past, the majority of humans lived in small settlements and the density of information was low. Many people now live in cities, and anyone visiting London or Berlin or New York will immediately appreciate the greater information density to be found in these places compared to that in hamlets or villages. Increasingly, people in developed nations work for knowledge-based companies that possess levels of information density exceeding those of cities. The suggestion is that the density of all four quantities will increase as civilisations become more advanced. And the logical end of this STEM compression? Well, the physical limit is set by the Planck scale. A black hole is thus the natural end of an advanced civilisation. It will be the natural end of our own civilisation.
One commendable aspect of the transcension hypothesis, at least to my mind, is that it offers specific and potentially falsifiable predictions – effects that astrophysicists could look for. (Read the book, or even better read John’s original paper, to learn more about those predictions.) However, is it reasonable to suppose that civilisations inevitably take a developmental path that leads to transcension? Well, John provides support for the idea by arguing from “evo-devo”, or evolutionary developmental biology. Evolution is a random process; development, though, is directed and constrained – a cat embryo gives rise to a cat, a dog embryo gives rise to a dog. Both evolution and development play important roles in life. What if the universe is engaged in a life cycle? (It was born in a Big Bang, it has grown as it aged, and there are processes relating to black holes that might allow it to spawn new universes.) If we live in an evo-devo universe then perhaps transcension is inevitable – just as an embryo gives rise to grown animal.
There are too many “if’s” in the argument for me to buy thetranscension hypothesis. However, in criticising the hypothesis I wrote that it requires that “all individual elements in all civilizations in all neighbouring galaxies develop in the same way”. This was one of those occasions where trying to compress information into a few lines (itself a symptom of STEM compression?) distorts the meaning. John sent a rebuttal to this, and rather than paraphrase it I’ll simply present it here:
Developmental processes are a very small subset of living processes. They certainly don’t comprise anything like “all individual elements” in an organism, and they ensure that evolutionary diversity grows over time within that organism, both within and across life cycles. If we live in an analogously evo devo universe, only a small subset of average observable changes in any civilization would be developmental. And those changes would be there to ensure that evolutionary diversity grows among civilizations over time, which is perhaps the main reason why we might have multiple civilizations and intelligent planets in our universe, if each is an incomplete and finite computational system.
I believe it will be worthwhile to examine the transcension hypothesis in more detail. Unlike so many “solutions” to the Fermi paradox, this one offers avenues for further research.