rn we're arguing about the discipline of the author's area of expertise. What we need to know is, what is the discipline of the doctors we're going to go get a second opinion from?
Not literature doctors (iow, philosophers), but science and perhaps engineering (I'm not sold engineers have any business in the discussion at all frankly, but as the author of the H.P.T., because engineer Walt Brown is an innovator and pioneer, his argument does have business in the discussion, and certainly). But mechanical engineering is not the science of the Earth itself as an object and as a physical mechanical system. The Earth is particularly studied by geologists, where GEO- literally means the Earth. The H.P.T., authored by a non-geologist, concerns the science of the Earth. Being a rocky planet, this is also the science of rock. So therefore, even though the engineer Walt Brown's legitimate area of legitimate expertise is on the periphery of the area of expertise which his theory applies to, the second opinions we most covet are those in that area of expertise, and not necessarily in the same area of expertise as Walt Brown.
Mechanical engineering concerns forces and matter, just like geology, but geology specializes the principles of mechanical engineering and science into the focus of the Earth in particular. Just because you're an engineer, doesn't mean you're going to be able to edit genes perfectly using Crisper, or even program a computer necessarily, but you've got an engineer's intuition or sense, the most distinctive feature of all engineers, that's common to all engineers, no matter the discipline. There's nothing wrong with any engineer tackling a physical mystery to try to understand it better, even if the area of expertise is on the periphery of the engineer's focus of study and knowledge. But the second opinions on that engineer's work, ought to be from a geologist, who is a mechanical engineer focused on the mechanical engineering of the Earth, but especially it would be nice if all the doctors largely agreed on the matter as well, that way it's easy to know how serious the second opinion is.
¹It doesn't mean that they're all right, if they're all in agreement; the doctors. That's an appeal to populism, which is a fallacy. They could all be wrong. It does mean that if all the geologists agree, and they are all wrong, that the second opinion is serious. (If they all agree and they are all right, this is what we expect from second opinions of other doctors. They all should agree with the first doctor, and they all should be right. That's the ideal, perfect situation, in terms of epistemology, the science of knowledge and certainty. I am not a doctor and I'm never going to be one, but that doesn't mean I just have no view in matters of medicine. My view is whatever my doctor tells me, especially if all the second opinions I get all confirm and corroborate my doctor. I don't have a more reliable heuristic for determining the truth of a medical matter, since I am not a doctor, and shall never become a doctor either. I still need to know medical things, and I can, since any doctor's opinion which is corroborated and confirmed by literally all the other doctors when you seek a second opinion, has high initial plausibility, meaning that if there are no defeaters for it, it becomes "foundational", which means self-evident, requiring no further argument to establish. The highest form of certainty, in terms of epistemology, in the top echelon along with tautologies and math. Foundational. H.P.T. has the potential to be foundational. Don't all you all want to know if it is? High initial plausibility and no defeaters. Foundational.
But even if it's not foundational, if all the doctors all agree on a theory, then there is high initial plausibility that some of the theories they all agree on are actually true, so it would be unsurprising if such a theory is actually true. It's not a strong argument until you try to identify legitimate defeaters.
The initial plausibility of any theory rises, the more questions are answered by the theory. If the defeaters for the theory are hard to understand for non-doctors, then there could be considerable confusion among them as to why not all doctors support a measure or therapy or treatment, which has high initial plausibility among non-doctors (but not among doctors). They might start getting conspiratorial (such as that they're working for Big Pharma for example). The fact is they don't understand the defeaters, they either think defeaters means a theory is defeated (it doesn't), or they think the defeaters are part of a conspiracy, or class warfare. But defeaters simply must be answered. (The ideal is that all defeaters are swallowed up and subsumed by the theory itself, which is when there are no defeaters anymore, which means the theory is obviously true, foundational, and self-evident. Think, "We hold these truths to be self-evident".)
How do I personally know whether the H.P.T. is self-evident? It's not possible, since I'm not a geologist, or a mechanical engineer. I have to rely on my doctor, and on all the second opinions of other doctors, because I myself am not a doctor, and I'm never going to become a doctor either, so therefore I require a heuristic to help me navigate these epistemological waters. I just think I need a doctor of geology when it comes to the H.P.T. second opinion. But see above!¹ All geology Ph.D.s might all agree the H.P.T. is wrong, but that wouldn't mean the H.P.T. is wrong. It would mean the initial plausibility of the H.P.T. is low, which means the theory has to be supported with evidence, more than defend itself against defeaters. A tougher row to hoe for sure, iow, compared with Relativity and Quantum and Evolution, all of which have high initial plausibility currently, among scientists generally. If you can't prove your defeater is real, then science itself isn't going to ever change its collective mind on the Standard Model of particle physics and Evolution. If all geology Ph.D.s think the H.P.T. is wrong, then positive evidence must be documented in its support. If they don't all think it's wrong, then you can just work on answering any proposed defeaters.