Pross, Addy. 2012. What is Life? How chemistry becomes biology. Oxford University Press. 200 pp.
I found this an interesting and generally readable book, but I think it promises more than it delivers. My reflections on it are rather lengthy, so I’ll begin with:
Prologue and Chapter 1
Pross’s question is, “What is Life?” His book is offered as an advance over Schrodinger’s 1944 essay, What is Life? He will use “Systems Chemistry” to state a new law on the “emergence, existence and nature,” of living things. He claims to have found an overlooked form of stability in nature. According to Pross, “Darwinism is just the biological manifestation of a broader physical-chemical description of natural forces.” This will allow him to put forward a “generalized theory of evolution.”
Like Schrodinger, he starts with the laws of thermodynamics – heat transfer, entropy, etc. He sees his task as like Schrodinger’s: to account for the stability of a living cell, despite its being far from thermodynamic equilibrium. He also wants to explain how the first one could arise. He says the goal of that understanding is to be able to synthesize a living organism from scratch. I wonder whether in his “generalized theory of evolution” there is a deliberate echo of general relativity? Does this point to scientific hubris or is it an attempt to pump us a thesis is that is really not all that revolutionary?
The discussion begins by identifying certain “strange” characteristics of life that he thinks are problematic: life’s organized complexity, its purposeful and dynamic character, diversity, far-from thermodynamic equilibrium state and chirality (the “handedness” of amino acids)
Like almost every discussion of the origin of living cells, his begins by emphasizing the cell’s complex structure. I think he confounds small size with intricacy of design, which is ok, if you want to compare a cell to a refrigerator, but it seems odd to claim that an eye is a less intricate design than the ribosomes in the cells the eye is composed of. He tries to define complexity in terms of organization. Does that make sense? He uses the shape of a boulder to define complexity one way – what would it take to describe it precisely, I guess he means. He introduces the idea of information at this point. He claims that as far as the definition of a boulder, the exact shape is arbitrary, implying that the information describing a living cell is less so, but is this only because he ignores the internal composition of the boulder, how it acquired its particular shape and the relation between composition and shape, etc? He points out that even tiny changes in DNA can alter a cell, but this is potentially true of boulders as well, if we alter the makeup or distribution of components. Also, both cells and boulders can vary in exact makeup over quite wide ranges.
He says organized complexity and the second law of thermodynamics are inherently opposed. Cells need energy to maintain their ordered state. Does this really mean complexity is opposed to the second law? I find that physical scientists and some biologists make a very big deal out of what seems to me to be an artifact of looking at their experimental subjects in isolation. The opposition only arises if you ignore part of the system – the biosphere as a whole. Pross admits that this is the reason for the apparent contradiction.
Now he sets up another straw man: Darwinian theory only deals with biological systems, so it can’t account for the origin of the first, self-replicator, the protobiont. Darwin’s theory is biological and does not try to account for the origin of life, but does that mean a Darwinian theory can’t? Darwin himself says that natural selection is the result of natural laws, including presumably, those of chemistry and physics. In fact, apart from these, what are biological laws? Geometric growth is in a sense purely mathematical, but arguably so is a lot of physics and chemistry. Genetic variation and struggle for existence, even natural selection, are expressible in mathematical language. His question, “how did a system capable of evolving come about in the first place?” seems wrongly expressed, possibly because evolving is not the fundamental thing. Darwin’s is a theory of the origin of species. Is evolution a capacity or a faculty of living things? It seems more like the overall pattern that emerges. The word evolution has that troubling sense of preordination or unfolding.
He brings up chance and talks about how unlikely a cell is to form spontaneously. I guess you have to rule that out at some point. He refers to the “first microscopic complexity” coming into being, which seems to ignore that things are “complex” at the microscopic level in many ways other than being living things. He does not begin his argument by saying self-replication is the fundamental defining character of life, which I think unnecessarily draws out his discussion.
Talking about the apparent purposiveness of living organisms, he uses the word “teleonomy,” a coinage designed to avoid the supposed meanings of “teleology.” Pross says our interactions with the non-living vs the living world have a different quality, because of living things’ teleonomic character. He says we don’t use teleonomic explanations in the non-living realm, but then why is he always saying systems seek a lower energy state? Is the conservation of energy teleonomic? We can think of machines as having needs and of animals as machines. Teleonomy is a function of our way of seeing the world, not a measurable property of things: you can certainly think of a rock as wanting to fall or electricity wanting to discharge itself, and contra Pross, you can get some guidance from the laws of physics about the likely behavior of animals as well as trying to read their intentions in postures and expressions or consulting your own likely responses (putting yourself in their shoes). He sets it up as a stark duality, but is it? He then lumps under teleonomy things as diverse as chemotaxis and human voluntary behavior. He also identifies function with teleonomy.
In his long discussion, Pross never mentions the telos of teleonomy: self replication. Pross’s rhetorical withholding continues. It gets murkier when he does bring it up, because he says, while we can have a lot of goals as a human, we need to look at simple organisms to get at the real one. So is our purposiveness different from that of living things generally? He refers to it as a powerful replicating drive. What does “drive” mean? He claims teleonomy is as “real” as gravity. But gravity is in some way fundamental, as the physicists say, or at least an aspect of something more fundamental still, while teleonomy seems a by-product of self-replication. Teleonomy cannot, can it, be unified with the other forces of physics. He says gravity is quantifiable and teleonomy is not but that it doesn’t make teleonomy less real. He claims we stake our lives on the teleonomic principle when we drive our cars. What does he mean? Is it the design of the car or my ability to drive it to where I want to go and avoid hitting obstacles or going over cliffs?
Part of the problem is he starts talking about a teleonomic principle, not just teleonomy. Where did the principle come from? Teleonomy seems like an analogy to our own purposiveness, but what laws govern it? Is there any real similarity? Is the analogy in any way useful to reasoning accurately about living things?
Pross says, “Metaphysically…gravity and teleonomy are mental constructs that assist us in organizing the world around us [does he mean sense data?] So is he an anti-realist in the school of Hume and logical positivism or a Realist of the idealist school like Kant? Then again, the Scholastic ideas of gravity and teleology are organizing principles. Is teleonomy like the Scholastic gravity, going to be swept away by a better concept? At one point, he says “all inferred patterns are conceptual and are found nowhere else than in our minds.” How closely can he stick to this principle, and in that case, what is his book going to explain, patterns in our minds?
I think simply admitting that self-replication is a property of living systems, and not the goal, would obviate the need for teleonomy. If there is a need to talk about “purpose” to avoid prolixity when describing biological structures and behaviors that are aspects of self-replication, we should just use the term and not invent new words because we fear someone will accuse us of teleological thinking. I wonder if these constant verbal contortions are because we are still fighting battles with those who identify the ultimate cause with a Creator whose plans are often crudely anthropomorphic, like his appearance.
In the section of life’s great variety, Pross says, “non-living diversity is arbitrary.” That hardly seems true of geology or the atmosphere. Perhaps he means it is easier to see the relatedness of living organisms: classification of plants and animals by non-literate people is often very close to the scientific classification. He repeats the false characterization of species as, “each perfectly adapted to function and survive in its particular ecological niche.” So, he’s not an ecologist or evolutionary biologist, but even popular books like those by Steven Jay Gould warn against that sort of talk.
He claims further that there is an inescapable contradiction between the principle of natural selection and the principle of divergence [of character]. Again, this is not a bad point to bring up, but if it really were a contradiction, then something would be seriously wrong with our theories on the origin of species, and this is not the case. There is nothing preventing diverse things from being selected. If the conditions of life were always and everywhere identical, then selection would prevent divergence. The problem goes away once you include the idea that organisms exist in varying environments. He seems to confuse debates over mechanisms of speciation with debates over these two principles.
In the section on life’s far-from-equilibrium state, he seems to be setting up a straw man to knock over later. Yes, non-equilibrium thermodynamics is exceptional, but it is not confined to living things. The lithosphere, hydrosphere and atmosphere are not in equilibrium, so why should it be surprising that processes occurred at some point that led to small parts of these moving further from equilibrium? As long as there is sunshine and radioactive decay, there’s the possibility of a system being supplied with enough energy to move it far from equilibrium. By far the trickiest part is to get the autocatalytic process going in an environment where it can be safe from degradation long enough to become robust enough to deal with the challenges of a changing environment and to diversify so as to occupy more places. But with no competition from already-existing organisms and billions of years…
I suspect the mystery of chirality (as he calls it) will prove to be another straw man. A phenomenon to be explained, yes, but not really that much of a mystery, at least not in the sense of requiring new principles to account for it.
His claim that we fully understand and can explain the characteristics of water or other inorganic substances, while we can’t understand living things also seems problematic. Do we really know all there is to be known about water? Again, he seems to be trying to hype up the level of mystery, instead of just saying that it’s a really complex problem. This would make his supposedly new principle seem more marvelous, I suppose. His promise is that he will reveal the hitherto hidden essence of life. TO BE CONTINUED.