Definition is the Problem
I have often been frustrated by creationists claiming that evolution can’t explain the origins of life, but even more irritated when evolution’s defenders try to halt the discussion by saying that “Evolution doesn’t address abiogenesis, evolution starts when the first life appears.”
Granted, my background and training are insufficient to explain or understand the full range of possibilities for abiogenesis, but it seems clear to me that the first life had precursors which evolved. Abiogenesis is presented as a “Holy Grail” of sorts, something for which we lack the fossil evidence and will likely never find, and that science is still “in the dark” on the issue. I have a problem with the idea that there may have been an abiogenesis “event” that anyone would ever be able to clearly mark as the start of life and then evolution.
The definition of “life” is not a clear one. It seems to me like the definition of a planet. Planets were once defined as objects which move in regular orbits in our skies, and even the moon and the sun were considered planets. As astronomical discoveries advanced, the definition of the word planet became much more problematic as early as 1801 when Piazza discovered Ceres. It wasn’t considered a planet because it was small, and yet it has a regular orbit. The International Astronomical Union upset school children and astrologers when they “demoted” Pluto from “planet” to “minor planet” with a new definition of the word. I was amused that astrologers complained about not being consulted, because it screwed up all of their charts. How? Changing the nomenclature doesn’t change its essence.
The same problem exists with life. Abiogenesis is not limited by nature to a single event, it is limited by our ability to clearly define life. The more that investigators learn about early replicators, the more they understand how complex the definition has to be. Nick Matzke addresses the point over at the Panda’s Thumb, in which he clearly shows that the mystery of the Origin of Life that scientists are supposedly “In the dark” about is not intractable, and the claims that said mystery is being addressed by intelligent design (phhfft.) Nick explains how both the attackers and defenders of this issue are wrong:
This mini-debate points out what I think, and have often said in conversations, is a major flaw in how we respond to creationists. All too often, when the OOL comes up in popular discussions (reporters, online debates, etc.), the anti-creationist will reply with some variation of “sure, it’s a tough unsolved problem, but we’re working on it”, or the wizened statement “actually, the OOL is outside of the domain of evolutionary biology”, or finally, “we’re pretty much in the dark about the OOL, but at least what we have is better than the creationists giving up and saying a miracle occurred.”
My take: It is high time all of these statements be discarded or highly modified. They are basically lazy, all-too-easy responses relying on hair-splitting technicalities or nearly philosophical assertions of the “even if the creationists were empirically correct on this point, which they aren’t but I’m too busy to back it up right now, it wouldn’t matter” variety. And the worst part is that these sorts of statements mis-describe the actual state of the science among the people who work in the field. It is simply not true that we, the scientific community, know almost nothing about the OOL (what an individual who spent a career working on fossils or fruit flies or speciation might know personally is a different question).
Even though Nick says he is pretty busy right now, he does address the question and illustrates where scientists are looking now and have been looking for the last half century on the Origins of Life.
Another creationist trope Nick addresses is the idea that Darwin had no idea of the complexity of the cell ( emphasis mine: )
To get an idea of that, let’s read some Darwin. This from near the end of Darwin’s 1868 book on the mechanisms of inheritance, The variation of animals and plants under domestication, page 404. Darwin proposed the idea of “pangenesis”, which was that heredity worked by each part of the body sending “gemmules” to the reproductive organs. This idea was wrong in detail but was an important step towards the eventual discovery of “genes” (so named after pangenesis). At any rate, Darwin thought a bit about what his hypothesis of heredity, or any similar hypothesis, said about the complexity of life:
Finally, the power of propagation possessed by each separate cell, using the term in its largest sense, determines the reproduction, the variability, the development and renovation of each living organism. No other attempt, as far as I am aware, has been made, imperfect as this confessedly is, to connect under one point of view these several grand classes of facts. We cannot fathom the marvellous complexity of an organic being; but on the hypothesis here advanced this complexity is much increased. Each living creature must be looked at as a microcosm – a little universe, formed of a host of self-propagating organisms, inconceivably minute and as numerous as the stars in heaven.
Bam. It appears that everyone was wrong – scientists who sometimes made a minor offhand remark saying people used to think the cell was simple, and creationists who made a major talking point of this, and Slack who heard it so many times from creationists/IDists, without prominent contradiction from scientists that he believed it himself. Like various dubious statement about the OOL which I discussed above, the “Darwin thought the cell was simple” statement became an unquestioned factoid merely through creationist repetition and flawed assumptions from the critics of creationists – it seemed reasonable, nothing crucial hung on it for scientists so they didn’t bother to double check in a serious way, and besides it is a lot easier to agree with your opponent and declare on other grounds that their point is irrelevant to the fundamental issues, than to do a serious analysis. It might be true that a creationists’ point is irrelevant to the bigger issues, but it lets the creationists get away with something that should not be gotten away with, and through an accumulation of such points the creationists build up a body of claims that even sincere, intelligent, creationist-skeptical, reasonably well-informed people like Gordy Slack find reasonable. Then you get essays like the one Slack produced, and irate responses that shed heat rather than light, and encouragement for the creationist leaders to feel like they’re on the right track.
If the Clashing Culture war over evolution is to be won based on the examination of the data, conceding incorrect points gives creationists ammunition. People who care about evolution really need to address all of the faulty points and not concede points as important as the 19th century view of the cell.
If philosophers of science can ever fix a definition of the demarcation between life and its precursors, then a reasonable mark between them can be used in the defense of evolution. Until and if that happens, the defenders are making a mistake by falling back on “evolution doesn’t start until life does.”
Abiogenesis happened in genesis. The way I see it, the steps between being “formed from dust” and having “the breath of life” are evolution. As usual there is no conflict, except for those who refuse to think things through.
[...] Haubrich at Clashing Culture discusses the definition problem: Abiogenesis [the rise of life] is not limited by nature to a [...]
Great post! Read in parallel with the Panda’s Thumb article, you make a lot of sense.
I’ve always been puzzled by the idea that the origin of life is outside the purview of evolution. I think that idea takes too narrow a view of evolution, decoupling it from the rest of the sciences and our understanding of the universe.
Evolution is not a stand-alone theory, wholly independent from the rest of the sciences; it forms a link or two in the chain of our understanding. That understanding requires many different disciplines, including astronomy, biology, cosmology, and geology to name just a few.
Even if evolution did not concern itself with the rise of life from non-life, science in some why would look at that. It must, as science is the way we understand our physical world. And the rise of life happened, without question, in the physical world.
How are you defining “evolution” here? By many definitions, it’s true that evolution doesn’t address the origin of life. I don’t think your main issue is with “Creationists” (which you should define as well) but with those non-creationist scientists who define evolution to not include the origins of life.
It seems that the arguments you are trying to make are not really geared toward the issue of discovering the origins of life or whether evolution did have a part to play in the OOL, but rather to drown out dissenting voices. There’s a big difference between discussions geared toward discovery, and those merely designed to fortify already entrenched positions.
Well, I hope that I had made clear that my complaint in this particular case was aimed at evolution’s defenders who don’t want to tread this ground because it is “too complicated for creationists” to understand. I think, in actuality it is a cop-out.
As for the definition of evolution that I am using here is the one that states that evolution is descent with modification, modification being a function of changes in biotic/prebiotic structures as they respond to environmental pressures.
My main point is that the definition between life and non-life is not solidly fixed enough in the philosophy of science to make the statement that there is a hard line that can be drawn between “evolution” and “abiogenesis.”
As to your final comment, I really need think that in order for you to get that chip off your shoulder you should take a biology class or two. My complaint is that in responding to strawman complaints against evolution, defenders of science should engage in the discussion in order to show creationists (inclusive of OEC, YEC, ID and exclusive of TE) where their arguments fail, and not to back off on this issue.
It’s a teaching opportunity for those who have ears to hear. I hope that here at Clashing Culture we have made clear that this is not an anti-religious site. See Anastasia’s brief, but extraordinarily clear, comment.
Thanks, Frank. And the point that you make about evolution is important. It relies upon and informs so many of the other sciences that it can’t honestly be separated out.
The point I always hear from creationists is that the theory of evolution does not explain the beginning of life. Are you saying that it is wrong to reply that the TOE was not come up with to answer that question?
I’m saying that it is a teaching moment to explain more about abiogenesis, and that simply saying that abiogenesis and evolution are separate is a cop-out.
If I can take a stab at this…
Evolution is the change of a system through time, while Darwinian natural selection is the mechanism of that change. At its core, natural selection requires that there be:
1. variation among individuals, that
2. can be passed on to “progeny” (however defined), that
3. makes a difference in how many progeny they are likely to have, which means that
4. in the future the variants that are relatively more successful at reproduction than the rest of the population will be relatively more abundant.
Once you have cells that can reproduce by dividing, its easy to see how this goes down the road, but what about before you have cells? Well, note that there is nothing in that list that requires individual organisms, or cells, or even biological life for this process to happen (the mathematical field of Genetic Algorithms is just one example).
The thing about the law of natural selection that most people, and even many biologists, fail to realize is that it is as much a natural law as thermodynamics — if those conditions are met, it WILL occur, no matter what.
So consider the following series of events:
It is well established that in the conditions present on the early earth (liquid water with a constant input of energy to keep it in a far from equilibrium state) that a huge number of molecules are formed. This satisfies condition #1 for sure, if you consider these molecules to be “individuals”.
There’s also the huge number of niches that were available on the early earth. Colder, hotter, sunnier, shadier, with huge variation in what minerals are locally available, and so there are many variations being constantly tried out.
Once these molecules are formed, they persist until they react with something else. The more stable molecules will persist longer, so over time there will be more of those stable molecules. This is ALMOST condition #3, but its simply a rate-of-decay difference. The important thing lacking is iteration: the winners in one “generation” getting a bigger share of the next.
However, the instant that any molecules are formed that promote their own replication in even the slightest amount (either directly, by some sort of RNA base pairing mechanism, or indirectly, by improving the local chemical environment such that molecules like themselves are more likely to be produced by the constant chemical reactions) then condition #2 is satisfied, and natural selection WILL begin to increase their abundance, giving you condition #4.
Just as surely as thermodynamics will begin moving heat from warmer areas to colder ones as soon as a difference is established, as soon as the capacity for iteration arises, natural selection begins to act. And all it takes is one niche to begin support this — once a niche is established, it will be constantly sending out “seeds” to nearby niches, and the selective pressure to be capable of colonizing them will be intense.
While broadly in sympathy with your motives, I disagree with your perspective regarding the origin of life. I’ve (I hope not impertinently) linked your post over at my blog (http://jo5ef.blogspot.com/) in order to develop some of my own thoughts on this issue.
My main point: its OK to admit we don’t yet have a fully fledged scientific explanation for the origin of life.
The way I see it, we philosophers and scientists have on one hand a yearning to incorporate evolution into a theory of everything. I saw a great presentation at an AAAS meeting a few years ago about teaching biological evolution as an integral part of a grand schema of cosmological change. What a great way to understand ‘theory’ and ‘law’ and ‘change’ but in a broad view of existence?
But on the other hand we scientists and philosophers are tied to our definitions. We demarcate and categorize and subdivide in order to better understand everything. I can’t begin to understand the astrophysics that belies cosmology – at least not without Brian Greene’s help.
These two opposing tendencies created the challenge of reductionism even before irreducible complexity came onto the scene. Science is intertwined with this tension, making it easier to conflate evolution, natural selection, and OOL.
Like Anastasia says, Genesis is a story of abiogenesis. In the end, I think that’s why OOL and evolution are so linked. It’s too easy to use the same words but attach different (but similar sounding) definitions. Which brings me back to why I think we need newer innovative ways to teach science.
I disagree with your strategy. However, I’m not very well versed in origin of life hypotheses. I am in the process of learning about them.
But in any case, as I see it currently, the evidence for evolution, in the origin of species sense, is very strong. The evidence for evolution, in the origin of life sense, is much more hypothetical.
There is a natural demarcation point between the two, and it is actually very important to separate them when discussing with IDers/creationists.
It is a strategy of IDers/creationists to attack the weak points (origin of life) and play it off like those same attacks apply towards the strong points (origin of species and all that entails). It is important to stop that nonsense in its tracks.