Morowitz takes us on a whirlwind tour of 28 instances of emergence, from the Big Bang, through nucleosynthesis, planetary formation, the beginning of life, animals, primates, tools, language, and philosophy, to mention but a few. His aim is to show us both what has emerged on this admittedly anthropocentric journey, at which he is highly and informatively successful, and how it has emerged, at which he is rather less so.
His has an interesting tool for explaining emergence, that of "pruning rules", defined thus:
I have struggled to understand this concept as applied to emergence, because after Morowitz gives his brief definition, he uses the term without further explanation, as if it is now understood. (And he also doesn't use it that much, either, so there is little context from which to infer and abstract a meaning.) So, as I understand it (and I may be wrong), the "possible" occupies some vast phase space, and these pruning rules pare that space down to what actually occurs (and, presumably, make the resulting phase space have a more complex structure?). Then the pruned space is further reduced by the "frozen accidents" of history, leaving us with the specific historical route to consciousness we see on this planet. The idea seems to be that these pruning rules are consequences of the laws of science, and so will work universally, and provide more structure to emergence than do the ideas of pure frozen accident and contingent development. (So I might quibble with the labelling of the pre-pruned phase space as "the possible".)
This is an interesting concept, and the identification of the Pauli exclusion principle as one of these pruning laws is fascinating.
I very much like this concept of pruning rules, providing non-accidental structure at very many levels to the evolution of the universe, although little further emphasis is laid on this structuring concept throughout the work (possibly because the relevant laws have yet to be discovered). However, I believe there is also another feature at work, which is the emergent development of the (pre-or post-pruned) phase space. (This development is described brilliantly in Kauffman's Investigations.) As pruning and contingency occur, new things become possible, new regions of phase space open up due to "gateway events", and so potentially new kinds of pruning rules develop. One could either argue that one starts with a "big enough" phase space, much of which is inaccessible until the relevant gateway events have occurred, or that the non-predeterminable phase space is actually co-created by the events it supports. Either way, this concept of a growing unfolding phase space does not seem to be part of Morowitz' vision (or if it is, I didn't spot it in my reading).
And there is another concept that Morowitz seems to take as a given, which keeps intruding into the scientific discussion -- that of "God". In fact, the last few chapters of the book (after we have emerged in 28 steps to "spirit") is almost entirely taken up with concepts and history of this "God" concept. I have no argument with including the place of various religions within the emergence of civilisation and culture. But Morowitz seems to be taking it much further than this, and I completely fail to understand what points are being made in these chapters. To me, it is a lot of chat about a null referent, and I can't work out where Morowitz is being metaphorical and where literal. Even given the benefit of the doubt, if it is all metaphorical, it isn't an interesting or helpful metaphor, as I can't work out what it is a metaphor of. I don't think it adds anything to the argument. (Well, it certainly didn't for me.)
In summary: this is a good description of emergence from the Big Bang to us, in 28 erudite bite-sized steps, with an interesting, if underused, idea of physically-based pruning rules. (The comments about the Pauli exclusion principle alone probably make the reading effort worthwhile.) But it seems to miss the accompanying concept of an unfolding evolving phase space. And the last few chapters can be safely skipped.
Combining geology, geochemistry, biochemistry, microbiology, evolution and statistical physics to create an inclusive picture of the living state, the authors develop the argument that the emergence of life was a necessary cascade of non-equilibrium phase transitions that opened new channels for chemical energy flow on Earth. This full colour and logically structured book introduces the main areas of significance and provides a well-ordered and accessible introduction to multiple literatures outside the confines of disciplinary specializations, as well as including an extensive bibliography to provide context and further reading.
For researchers, professionals entering the field, or specialists looking for a coherent overview, this text brings together diverse perspectives to form a unified picture of the origin of life and the ongoing organization of the biosphere.