We have seen in the last post (Part 1) that life is not conserved, while matter and energy are. We know that life is an emergent phenomenon from complex chemical interactions. As discussed in the last post, there are a multitude of complex systems that also emerge from physical and chemical interactions that are not alive. A storm emerges from a particular set of circumstances involving temperature, humidity, pressure and wind, and some of these (like wind) are themselves emergent phenomena of more basic components (such as temperature gradients in the atmosphere). A storm, as a complex system, can be said to be born as a result of accidental configurations that occur together in the right place at the right time. The storm will last for some period (its “lifetime”), and then “die” as the factors that keep it in homeostasis either dissipate or change due to other random, accidental events. If conditions of temperature and other factors are right, a random collision between two molecules in the atmosphere or the ocean may lead to a chemical reaction, producing the “birth” of a new compound. That compound will also remain in existence until it is in turn degraded by further chemical interactions, hydrolysis, or decomposition.
Furthermore, it appears that the processes by which complex systems are terminated or destroyed have much in common, whether those systems are alive or not. In each case, it isn’t matter or energy that is lost, but the complexity and regularity of the system itself. In each case, the homeostasis or maintenance of the system breaks down. A storm travels over land and dissipates its energy; the wind dies down, the rain clouds scatter. A complex chemical compound undergoes hydrolysis, bonds are broken, and the chemical is transformed to a simpler one. A star runs out of nuclear fuel. Sometimes such death events are accidental, and sometimes they are inevitable, predictable part of the process of the system.
However these systems, while they share the features of complexity, emergence, and decomposition with life, do not undergo natural selection, because (as we saw in the last post), they lack inheritance: they have no inherent informational content that is passed to progeny.
But there is another major difference between life and nonlife that cannot be accounted for by physical laws. And that is teleology. Life operates with purpose – it is goal oriented. That is a remarkable and highly controversial statement, but it is demonstrably true. Most people will agree that nonbiological natural events are dysteleological: they occur with no purpose, no agency guiding them other than relevant physical laws and natural conditions. There are no agents that decide when a volcano will erupt except the accumulation of forces – forces that follow no plan and are not organized toward any purpose. The same is true for star birth, supernovas, storms, or spontaneous chemical reactions. Many will hold that the same is true for biological systems, but that is easily disproven, at least for modern systems (meaning all life since LUCA).
For almost the whole history of our planet, new living forms have been created from other living forms. Furthermore, this process, which we call reproduction, is planned, purposeful, and directed by specific biochemical processes. Every living entity on the earth today is the result of a teleological process built into the normal functioning of all living creatures by billions of years of evolution by natural selection. The critical biochemical pathways that make life purposeful are replication of the genetic information, reproduction of the organism, and translation of the genetic information into biological characteristics (the linkage between genotype and phenotype).
Each of these biochemical processes are highly purposeful. They do not occur at random, depending on accidental appearances of forces or material, but are well controlled and very specific in timing and outcome. The agent of these processes (as well as of all the other processes required for life, such as energy conversion, biochemical synthesis, and homeostatis) is the living organism itself. While this might appear to be a circular statement, it follows directly from the uniquely biological law of natural selection.
Any allele p that is preserved and inherited, and leads to an increase in dY/dT, will increase in the population according to the population genetics law of selection:
where S is the selection coefficient related to fitness. Therefore, strong selection pressure for alleles (or new genes) that increase the ability of organisms to engage in the activities (such as reproduction or translation) that will maintain their existence results in an ever increasing dY/dT (meaning that the second derivative is positive).
Cells do not decide to improve themselves, but evolutionary processes do. And this is unique to biology. No storm system cares if it dies out or does not give rise to another storm. But bacteria, oak trees, and dolphins do care. Not consciously, of course, but as life becomes more and more complex, we can begin to see an actual will to survive (also part of evolutionary development) so that animals will flee predators, and parents will protect offspring.
This is not what Aristotle had in mind with his Telos. It is an automatic, non-conscious form of purpose (sometimes called internal teleology or teleonomy), but it is still purpose, and to deny its existence in life forms is to completely deny one of the most fundamental principles of biology, a principle that follows directly from the NCP and from evolution by natural selection.
Sy, since here you are directly discussing biology: what is the deal with so called junk DNA? I’ve jsut recently seen people argue about it, and have no idea whatsoever what to make of it. Help!
I think its pretty clear that some of the DNA regions that used to be called junk, simply because they do not code for proteins actually do have other functions, especially regulation of gene expression. However, that does not mean there is no junk DNA, we know that there are vast regions of genomes that consist of non functional repeats of nucleotides, there are almost large numbers of pseudogenes (“gene fossils” that are no longer active) viral insertions, and transposons. Some of these non functional elements could play a role in providing material for new genes, or for changes in gene expression. What we dont know yet with much certainty is how much of the genome is devoted to each of these categories of DNA. I think its likely that about 50% (give or take 20%) of the genome is really useless, and most of the rest has either a necessary or potentially useful function. This will likely also be different in different species, since most genome architecture is.
Thanks for the question, and yes, I am originally a biochemist, so this post is a foray into biological philosophy, something new for me.
Thank you for the fast answer, Sy. Seemingly it does not really affect your views on purpose in evolution.
Regarding philosophy of biology, how do you say: If the show fits, wear it! It seems to be a field that has too long be dominated by people that do not at all have a metaphysically balanced view on their profession. I’m thankful that you delve into that, sadly, often enough muddy mess that is todays debate on intrinsic teleology in nature
Yes I agree that the debate is muddy, partly because of imprecise definitions and partly because some folks are so desperate to make sure that no hint of any mystery or potential for divine presence is eliminated from biology, that they lose their scientific objectivity. But that is a whole nother story. Peace, and thanks for commenting here.