The last thing that I was expecting in response to my post on one of the lesser-known falsifications of Earth Expansion was a defence of their position as “valid philosophy”. But that’s just what we’ve got from Nick in the comments. I’m quoting the most relevant bits of his first and second comments below, but if you haven’t already you should go and read them in full.
But the question at hand about the Expanding Earth hypothesis is a bit harder to address, and I’m not quite sure that the blog really does. I have only crossed one EEer who I felt was intelligent enough to really get into it with. He really put it in perspective for me that the basic premise isn’t about the EEer’s need to ‘negatively test’ every hypothesis that is thrown his way, but is rather to point out that a “theory” is a house of cards that falls down when you pull one out. In the EEer’s case, the card to pull is “subduction”. Now, I am a (geologist masquerading as a) geophysicist, so I accept geophysical models of subduction zones. But if I didn’t, the whole tectonic paradigm might seem a bit thin. Each one of Wegner and deToit’s hypotheses is indirect – from the facies correlations to the pmag that came later. WE accept them because we work through them and are led to inescapable conclusions. But an EEer won’t go there, pointing out (perhaps correctly!) that each piece of the puzzle has a flaw…
…The point is that these guys aren’t creationists, they are valid philosophers.
Which brings me back to my point that these guys are practicing a legitimate form of philosophy. Not science, but philosophy. Creationists in contrast are practicing religion and ideology – i.e. not even challenging our science on its own grounds, saying the whole thing is wrong because it conflicts with their faith. A good EEer doesn’t challenge on the basis of their faith in EE, but does so as a cry against “group think” etc… >
I think that this line of argument is mistaken on a number of levels. Firstly, as far as I’m concerned Expanding Earthers are exactly the same as creationists and ID advocates: in both instances, its obvious that they have started with their conclusion. You can see this in the way that they charge around, picking up on any perceived error or inaccuracy and instantly proclaiming the scientific consensus dead. Even if they are accurately representing a real problem, they will never bother to demonstrate how it undermines an entire theoretical framework – apparently its mere existence is enough, even if it can be shown quite easily that this “fatal flaw” makes very little difference (I’ve noticed a similar attitude amongst the climate change denialists in the past). Then, by default – without bothering to present any argument why this should be the case – their own pet theory is “proven”.
There’s nothing wrong with giving the underlying premises which guide our thinking the occasional intellectual poke – there are many examples of times when a scientific field has been advanced by people doing so. But the EEers’ focus on subduction is nothing to do with the relative weaknesses of plate tectonics, and everything to do with the weaknesses of their own “theory”; it’s the one part of plate tectonics that quite clearly undermines an expanding earth. The point of the last post was that, regardless of whether or not we have a good handle on subduction, we have ample geological evidence that very large ocean basins have closed in the past – which is not something that you would see if the Earth was steadily getting larger over geological time. An intellectually honest plate tectonics skeptic cannot be an Expanding Earth proponent, because they would have to acknowledge that the latter theory is even less successful – it explains less and there are areas where it clearly contradicts the facts on the ground.
Secondly, I really, really have to take issue with this characterisation of a scientific theory like plate tectonics as a “house of cards” – knock out one fact, and the whole edifice comes tumbling down. This picture fundamentally misrepresents the way that all the different strands of evidence – the fossils, the palaeomagnetism, the fracture zone trends, the earthquake focal mechanisms, the sundered mountain chains, all the rest – interact with each other. The different individual “facts” are not arranged serially on top of one another, producing a tottering tower that could be sent tumbling by the smallest nudge on any individual part, but in parallel, with numerous independent lines of evidence providing support for the conclusion. This increases our confidence that we are least broadly on the right track; even if you knock out one strand of evidence, the others are still there, not at all dependent on the one you’ve just “disproved”, and requiring an explanation as to why they are all also pointing to the “wrong” answer.
As an example, we can return to those allegedly controversial subduction zones. A skeptic might highlight uncertainties in seismic tomography, which maps areas of the mantle with higher-than average seismic velocity dipping away from subduction zones; because the colder a rock is, the faster seismic waves can travel through it, these zones are usually interpreted as evidence for cold, subducting lithosphere. However, changes in composition can also effect seismic velocity – so how do we know for certain it’s due to temperature? Well, we don’t if you’re just looking at the tomography data, but there’s the fact that earthquakes extend much deeper in these high velocity zones, as you’d expect for colder and stronger bits of the mantle. Then there’s all the earthquake focal mechanisms which indicate convergence, and the fact you have volcanoes behind trenches, with melt compositions that are what you would expect from mantle melting triggered by the addition of water, in exactly the place you’d expect water to start being driven out of cold slab being pushed into the mantle and heated… So, we could be interpreting the seismic tomography wrongly, but the other possible interpretations are not consistent with all the other completely independent evidence. When you consider everything, subduction is the only explanation that works.
So what is a theory like? Not a house of cards, that’s for sure. It’s more like a table with 20 legs, solid as a rock even if you hack a couple away. Of course even that is beyond your average expanding earther; all they do is give the table a few kicks, bruise their shins and run away claiming they’ve turned it into matchsticks, when in reality all they’ve done is annoyed the geologists round the table by spilling a few drops of their beer.