First a general overview & appraisal of the book, and after that there’s a fairly lengthy section with quotes and paraphrases of nuggets of wisdom I want to keep on record, and those could be interesting for you too.
For starters, the summary on the back: “In this book, Russell Powell investigates whether we can use the patterns and processes of convergent evolution to make inferences about universal laws of life, on Earth and elsewhere. Weaving together disparate philosophical and empirical threads, Powell offers the first detailed analysis of the interplay between contingency and convergence in macroevolution, as it relates to both complex life in general and cognitively complex life in particular. If the evolution of mind is not a historical accident, the product of convergence rather than contingency, then, Powell asks, is mind likely to be an evolutionarily important feature of any living world?”
Or, as the MIT website states it in short: “Can we can use the patterns and processes of convergent evolution to make inferences about universal laws of life, on Earth and elsewhere?”
The book doesn’t presuppose a lot of working knowledge: Powell takes care to explain all the concepts and the history of science & philosophy one needs to understand his arguments. As such it is perfectly self-contained, BUT, mind you: this is hardcore stuff, it is not a popular science book at all. It has 280 pages of carefully and tightly argued text, there’s not a lot of redundancy, not even on the sentence level, and as such keeping a search engine at hand while reading this is no luxury.
There’s also 20 pages of biographical notes, and Powell has read wide and far on all kinds of matters to make his case: both evolutionary science in the biological sense, as well as evolutionary accounts of developmental psychology and sociology – of the kind I reviewed earlier with Tomasello’s Becoming Human: A Theory of Ontogeny, and science and philosophy on Umweltian cognition & phenomenology. There are also important chapters on invertebrate cognition, diving into the latest, cutting edge research on cephalopod minds and the surprising capacities of bees and other critters. It truly is an interdisciplinary intellectual feast, and I learned a lot.
While some might say this book at times could be to detailed for the layperson, I nevertheless – being a layperson – enjoyed it from cover to cover. I thought it was a delight being taken on an intellectual adventure that challenged my brain. Admittedly I’m not fully part of the target audience, but seeing Powell argue so meticulously was a treat in and of itself, and for scholars of evolutionary biology or professional theorists of mind the pleasure will only be bigger.
The book is divided into two parts, and I want to stress the different nature of part 1 and part 2: some readers could still find much of worth in part 2, even if they aren’t interested in all the details of part 1, and vice versa.
The first part starts with a chapter on the need for biotheoretical input in matters of cosmic astrobiology because of observer selection biases, and afterwards examines Gouldian concepts of convergent & contingent evolution in the broad sense, focusing on the evolution of bodies. Powell does what everybody that takes science seriously should do: he examines & tries to define the meaning of the concepts – something that is sadly too easily glossed over time and time again. As such this first half is also part critical reading of Stephen Jay Gould and other evolutionary theorists.
The second part zooms in on minds, and starts with an extremely interesting investigation of sensory modalities in various animals, as sensing your surroundings is crucial to develop a mind. It continues with a discussion of how animals perceive their surroundings and themselves in those surroundings, and what that means for the possible emergence of minds. The last two chapters then look at possible evidence on how minds – other than the minds in the brains of terrestrial vertebrates – could emerge from neuroanatomy and the convergent evolution of bilateral brains and other types of neural clusters, and at evidence from behavior – from cephalods and arthropods, as I referred to above.
The stunning coda makes the jump from minds to full fledged human-like culture, and offers a few cents on the Fermi paradox – a paradox well-known to the scifi readers of this blog.
Although Powell dares to make numerous pretty definitive claims, he also shows a lot of humility and restraint: “when all is said and done, most of the landscape will remain uncharted, and the mystery of mind will remain.”
The excellent and always informative blog The Inquisitive Biologist has already written a splendid in-depth account of the book here, especially of the first part, so be sure to read that first if you have any inclination to read it. I will also defer from further trying to summarize the book, as that review has done most of the work already. [update June 2022: Also Jeroen Admiraal, a biologist too, wrote a very accessible summary of the book on his blog, again with a focus on the first part.]
To end this part of the review, let me be loud and clear about it: this book is highly, highly recommended, easily a 5-star read, something rare indeed. I have already ordered 2018’s The Evolution of Moral Progress: A Biocultural Theory by Allen Buchanan and Powell, I’m very much looking forward to reading that, and I will be on the lookout for whatever Powell publishes next.
[update November 2021: The author today goes by the name of Rachell Powell.]
SOME TASTY TIDBITS
I will leave you with some of the nuggets I’ve learned while reading Contingency and Convergence : Toward a Cosmic Biology of Body and Mind. The usual caveats apply: these nuggets are not a summary at all, and are not intended as a representative sample of the actual content of the book. They are just here as a reminder for myself, and maybe some of them will delight you too. They might, however, show a wee bit of the rich, broad scope of Powell’s book – that is, if you factor in this reader’s selection bias.
> ‘Contingent’ is not the same as ‘unpredictable’ or ‘nonrepeatable’.
> We cannot observe minds. What we can observe are brains and behavior (“the causal signatures of minds in the world”).
> Like I already learned from Rosenberg’s brilliant book Darwinian Reductionism, biology is an historical science. It is not law-based, like the study of stars. Powell’s book is a cautious attempt to see how much biology on Earth could learn us about possible biological laws in the larger cosmos.
> Carl Woese and his collaborators’ work implies that “there was no single, discrete common ancestor of all extant life. Instead, there was a single ancestral communal population. On this view, proper “tree-like” evolution, with clean lines of vertical descent, would not come until later in life’s story.”
> Viz. the Copernican notion that the universe must be teeming with complex intelligent life, similar to our own: “We cannot infer from what did happen to what had to happen purely on the basis of statistics.”
> Molten metal planet cores are important as they support magnetospheres, “which deflect solar winds that would otherwise deplete atmospheres, as appears to have doomed the early Mars”.
> Extinction events (stochastic or pseudo-stochastic) “cut deeply into the possibility of a law-like shape of life.”
> “lineages do not get better at not going extinct over time as one might expect they would if evolution were a gradual optimizing process”
> “Also likely to be universal is the non-meritorious culling power of mass extinctions. Life will tend to evolve on geophysically dynamic planets, and the downside of living on a geophysically dynamic planet is that it comes with the occasional mass perturbation due to volcanism, tectonic movement, asteroid impact, climatic change, and the like.”
> “not only are the concepts of contingency and predictability severable, they describe entirely different categories of thing: metaphysical states of the universe, on the one hand, and knowledge states about metaphysical states of the universe, on the other. Although determinism and predictability bear important relations to one another, it is also easy to see how the two come apart and why their conflation is problematic. For instance, chaotic dynamical systems are deterministic, yet they are in principle unpredictable; quantum mechanical systems are irreducibly indeterministic, yet they support the greatest predictive precision ever achieved by a human science. Even comparatively simple deterministic system will support prediction only to the extent that the laws of nature can be know, present states ascertained, and future states computed by the cognizer in question. The “n-body problem” (…) shows that even for Newtonian systems involving only three bodies (…) attempts to derive future states of the system can be intractable. Thus, whether the universe or some relevant subset of it is deterministic is a metaphysical question that is wholly distinct from the question of whether future states can be predicted by any given cognizer. It follows that whether macroevolution is radically contingent is a metaphysical question that is decidedly not determined by the knowledge state of any observer.” (It is not prediction or not but causal structure that makes contingent, contingency has to do with metaphysics, not with epistemology.)
> “Biological indeterminism is not, substantively speaking, an implausible position, as irreducibly chancy events may very well “percolate up” from the quantum level to affect evolutionary trajectories. This percolation may occur, for example, through proton tunneling that affects which mutations arise or in what order they do so. Or it may occur through quantum alterations of microscopic initial conditions on which chaotic geophysical systems (such as weather, climate, tectonics, etc.) are sensitively dependent, with chaotic dynamics magnifying these events to the point that they influence large-scale selective environments.” (But as far as I can grasp, this is not an (theoretical) argument against biological determinism as it is generally understood, in the causal sense of the word.)
> “The standing humanoid epidemic in science fiction is not due solely to the limitations of imagination or the pragmatic demands of cinema. Nor can it be chalked up to an ignorance of the disparate body plans in which terrestrial intelligence has arisen. Rather, there is predilection to infer from what did happen in evolution to what had to happen, and this tendency is underwritten by the bundling bias.”
> There are single-celled eukaryotes that have camera eyes, sculpted out of subcellular organelles!
> Light, sound and electromagnetic fields are types of waveform energy that can carry “ecologically useful information about the distribution of objects and their properties”. “Other energy stimuli, such as chemical gradients that serve as the basis of olfaction, do not carry information that can underwrite a three-dimensional perceptual world that supports sophisticated locomotion, navigation, predation, and other cognitive-mediated behaviors. (…) olfaction is informationally impoverished when it comes to forming real-time images of objects that comprise scenes.”
> Echolocation (bats, thooted whales) and electrolocation (certain fish) can be considered to be equivalent to vision: they allow the animal a similar real-time, 3D, fine-grained image of their surroundings, and they even allow for cross-modal recognition in species that can also see.
> “it is chemistry rather than physics that distinguishes biology from technology.” (quoted from Land and Nilsson)
> It’s obvious, but bears repeating: there are numerous organisms that transfer information through other means than neurons. Also plants, unicellular eukaryotes and bacteria all “exhibit functional analogs to memory and learning that are decoupled from metabolism.”
> It is very difficult to define ‘neuron’. (as pointed out by William Kristan)
> Brains integrate vast amounts of information by virtue of recursive interchanges.
> There is, so far, “at least one study showing that ants pass the mirror self-recognition test.” That might say something about that test, or about self-recognition being not the same as self-awareness “in a thick narrativistic sense”. Either way, remarkable.
> “In short, emotions are action-tendencies that include a cognitive appraisal of some internally modeled state of affairs in the world and an accompanying somatic state or “feeling,” which together generate appropriate action (such as approach or avoidance). Actions like visual search would arguably be impossible without affective valences being attached to perceived objects and outcomes. Neuroscientist Antonio Damasio argues that action is often guided by the “fainter image of an ’emotional’ body state, without having to reenact it in the body proper.” Damasio conjectures that these affective markers, or “as-if” emotional simulations, are trained up over the course of ontogeny and permit rapid decision-making by bypassing the slow and energetically costly experience of a full-blown emotional state. These “as-if” feelings occur outside of attention or conscious awareness.” One could hence argue insects must have “affective capacities.” (On a personal note, as I observe my children (and myself) growing a bit older, there is something to be said for that ontogenetic shift from full-blown emotional states to fainter images of those states.)
> The evolution of human-grade technological capacities – a cumulative culture – is based on a “formidable suite of contingencies” that “have been largely overlooked, and as a result the fraction of evolutionary histories that are expected to lead to robust technological civilizations has been overestimated.”
> Morals and constructed learning environments can be considered social technologies. (This part of the book ties in to the ethical part of Tomasello’s Becoming Human, which I already linked to at the very beginning.)
> Nor symbolic culture, nor language, nor morality by themselves or taken together necessarily lead to a cumulative culture as we are living it since about 40,000 years or so, again amplified by the agricultural revolution, and the industrial and scientific revolutions.
> “In a break from nearly all of human history, technologies that are ubiquitous today bear essentially no resemblance to technologies that are hundreds or thousands, let alone millions, of years old.” Powell doesn’t say this, but might I end with pointing at the potential disrupting nature of this remarkable fact? Others have written about small aspects of it, like Bakker and Auerbach, and it’s obviously ironic that because of it, we humans also contribute to the planetary geophysically dynamism Powell wrote about in one of the quotes above.