In an earlier post, I wrote that my faith in Intelligent Design was falsifiable, and I listed two criteria by which it might be falsified:
1. An empirical or mathematical demonstration that the probability of the emergence of life on Earth during the past four billion years as a result of purely natural processes, without any intelligent guidance and starting from a random assortment of organic chemicals, is greater than 10^(-120). [Note: when I wrote “life,” I meant “cellular life.”]
2. An empirical or mathematical demonstration that the probability of the emergence of any of the irreducibly complex structures listed on this page, as a result of non-foresighted processes (“random mutations plus natural selection”) is greater than 10^(-120).
I could have added:
3. An empirical or mathematical demonstration that the probability of the emergence of eukaryotes from prokaryotes, or of the 30+ phyla of animals from a single-celled ancestor, or of the different classes of vertebrates from a common ancestor, as a result of non-foresighted processes (“random mutations plus natural selection”) is greater than 10^(-120). Indeed, I might have added “orders” and “families.”
In my post, I deliberately set the bar very, very low, in terms of probabilities – in fact, quite a bit lower than I need have done. I wanted to be as generous as possible to skeptics who might argue that a lot might happen in a large cosmos, over a long enough time.
Astonishingly, no-one in the “skeptic” camp took up the challenge. I was genuinely surprised, because I wasn’t asking for much.
I didn’t ask for a detailed step-by-step pathway. I didn’t ask for a calculation of the number of steps involved. I didn’t ask for a detailed description of the starting point or end point of these evolutionary transformations. I didn’t ask for a detailed description of the evolutionary mechanism. All I wanted was a feasibility demonstration – what we might call a “proof of concept.” And I wasn’t asking for proof that the proposed mechanism (commonly dubbed “random mutations plus natural selection”) would work. All I wanted was a rigorous mathematical or empirical argument that there was a probability greater than 1 in 10^120 that it could work, over a four-billion-year time period. A back-of-the-envelope calculation would have satisfied me, had it been to the point. A scientific model of the changes involved, which allowed a rough calculation of the probability of their occurrence as a result of “random mutations plus natural selection” over a specified time-period, would have been even nicer.
A scientific demonstration, based on probabilistic arguments (e.g. nested hierarchies), that we all sprang from a common ancestral stock, would have been missing the point. I already accept that. For me, the question is: did the variety of life-forms and complex biological structures in the cell that we see today develop from this common ancestor as a result of processes requiring intelligent foresight, or as a result of processes requiring none?
I am aware of the common evolutionary argument that the only known processes which automatically generate nested hierarchies are memoryless Markov processes, which certainly accords well with the neo-Darwinian claim that “random mutations plus natural selection” are responsible for the diversity of life on Earth today. But that’s a question-begging argument. If there was a natural, non-foresighted process which generated these nested hierarchies, then it must have been a Markov process. But that doesn’t help me, if I’m also aware of various features of living things – such as a very high degree of specified complexity – which on the face of it, could not have been generated by non-foresighted processes (i.e. “random mutations plus natural selection”).
A paleontological “argument from ridicule”, along the lines of “If you believe that whales are descended from land animals, and that the process was engineered by God, why didn’t God perform the transformation from a land animal to a whale instantaneously, instead of taking ten million years?” would not have convinced me either. For the question contains a number of unwarranted assumptions. It assumes that a modern whale would have been able to out-compete a transitional form such as Rodhocetus, if it were alive back then, which is doubtful, as Rodhocetus was amphibious: it lived on the land as well as in the sea. It assumes that there were no environmental conditions 47 million years ago, that would have been unfavorable to modern whales, despite the fact that there was actually a very marked climate change 35 million years ago, from a “greenhouse Earth” to an “icehouse Earth.” The question also assumes that there would have been suitable food for modern whales in the oceans, back in those times. Furthermore, it assumes that the sudden appearance of whales 47 million years ago would not have caused any major ecological disruptions – which is quite an assumption to make, when some scientists are now telling us that a tiny increase (in absolute terms) in atmospheric carbon dioxide levels, from 0.04% to 0.08%, will eventually result in the extinction of a quarter of the world’s species (and perhaps more). And finally, the question assumes that an ancestral land animal could have given birth to a modern whale produced by Divine genetic engineering, without dying in the process 🙂
A hectoring philosophical argument, treating common ancestry as a solid fact and then eliminating evolution guided by an Intelligent Designer as an explanation, by an appeal to Occam’s razor, would also have been missing the point I wanted to make. My belief in common ancestry is not rock solid. It’s tentative. If you insist on ruling out an Intelligent Designer at the very outset, and if you refuse to provide me with a demonstration that the (seemingly) massively improbable life-forms and biological structures we see around us today are, in fact, within the bounds of what we might reasonably expect, in a large cosmos, over a four-billion-year time period (or 14 billion years, if you want to go back to the Big Bang) – i.e. that the likelihood of their emergence is greater than 10^(-120) – then I will give up my belief in common ancestry. Any rational person would do likewise.
“Why?” you ask. Let’s flash back to 2007. In that year, the Intergovernmental Panel on Climate Change prepared a Summary for Policymakers in which they declared, “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG [greenhouse gas – VJT] concentrations” (page 5). In their Guidance Notes for Lead Authors of the IPCC Fourth Assessment Report on Addressing Uncertainties, they obligingly defined “very likely” as “>90% probability.”
Now imagine an IPCC scientist briefing a policymaker about the latest findings. In the middle of the briefing, a policymaker interrupts the presentation with a question: “Can you show us a scientific calculation to support your claim that the Earth is going to heat up by somewhere between 1.5 and 4.5 degrees in the 21st century?” The scientist, if he/she is well-informed, will respond, “Yes. We have dozens of computer models of the effects of doubling CO2 in the atmosphere. And while some of them show more warming than others, all of them show warming to some extent – with the vast majority showing a warming between 1.5 and 4.5 degrees. That’s why we’re more than 90% sure that Earth will heat up to that extent.” That is doubtless how a climatologist would have responded, three years ago. (It seems like an eternity ago now, doesn’t it?)
But suppose that the scientist had said, “Actually, we can’t demonstrate, in numerical terms, the likelihood of the Earth’s heating up by between 1.5 and 4.5 degrees Celsius next century, as you ask. We’re not in a position to do that. We don’t have the kind of models that you would need in order to perform such a calculation. Nevertheless, we are quite confident that the Earth is heating up – so much so that ‘if you meet somebody who claims not to believe in global warming, that person is ignorant, stupid or insane (or wicked, but I’d rather not consider that).’ The range of 1.5 to 4.5 degrees represents our best estimate. If you don’t like it, you can lump it.” What do you think the policymaker’s reaction, as a layperson, would have been? Some rather unprintable remarks about the arrogance of scientists, I’d be willing to bet! (My apologies to Richard Dawkins for “adapting” his quote, but I just couldn’t resist.)
The authors of the IPCC report were nothing if not politically canny. They realized the psychological importance of the 90% figure. For most of us, that’s near enough to certain. But oddly enough, the purveyors of neo-Darwinian evolution are far less canny. The case for neo-Darwinian evolution has a mile-wide gaping logical hole in it, and its proponents are doing nothing to plug it. This hole even has a name: it’s called a causally adequate mechanism. But NDE proponents are simply hoping that the public won’t notice the hole. How dumb is that?
Let me put it another way. At the present time, it would be more rational to believe that the fairies at the bottom of the garden produced the diversity of life-forms we see on Earth today from a common ancestor, than that “random mutations plus natural selection” did the job. “Really?” I hear you ask. Yes, really. Lots of sincere people have claimed to have seen them throughout history (if you don’t believe me, see here and here), so I suppose one would have to rate the chances of their being real as somewhat greater than 10^(-120), despite their extremely bizarre behavior (according to folklore) and the total absence of credible photographic evidence for fairies. And if one is prepared to grant that fairies just might exist, then one should also grant that for all we know, they may have existed four billion years ago, at the dawn of life on Earth. Interestingly, Theosophists believe even now that fairies are real, and that they – or more accurately, their larger spiritual cousins, the devas – actually guided the process of evolution! Fairies are after all intelligent, and intelligent beings are the only beings known to be capable of generating large amounts of specified complexity. In other words, fairies are at least an adequate cause of the high degree of specified complexity we observe in living things. Random mutations, natural selection and other “non-foresighted” processes, are not. They lack causal adequacy.
So what was it that generated the Cambrian explosion? Well, as a Christian and a theist, I’d say “God,” but if you gave me only two choices – fairies, or random mutations plus natural selection – I’d go with the fairies, every time. Any rational person would, given the current state of the scientific evidence.