Re: materialism, Joe wrote, "Why believe in any scientific experiment? After all, they all are materialistic."
They aren't. Most of the truly great scientific advances have been from rejecting materialism, not insisting on it.
Newton's action-at-a-distance in describing gravity required rejecting materialism, to the dismay of many then and now. Yet to this day no one has demonstrated a materialist explanation, not even under general relativity.
Adam Smith's invisible hand and Ronald Coase's theorem reach far beyond materialism for their insights.
QM, and its prodigious fruit (computers, lasers, amplifiers, etc.) are built on a rejection of materialism. The double-slit lamp experiment, voted by physicists as the greatest of all time, disproves pure materialism. In response, materialists simply ignore it rather than search for further insights that it may yield.
Joe wrote, "At what point does Andy just say 'Sorry, we have in this particular case something that is obviously unexplainable by the scientific method, so let's go on to another question, because we have a stone wall here that we can in principle never get through?' Sounds like migration of birds may well be one of these mystery areas."
No, I don't agree. Migration should and will be understood far better than it is now, but only by looking beyond materialistic approaches like magnetism. I'm sure glad Newton wasn't a materialist and was able to accept action-at-a-distance. Aren't you?
Re: the lobster/magnetism grad project, I wrote, "the grad student should test lobster movement under a 100 or so different magnetic fields, and see if there is any correlation."
Roger replied, "I bet he did do it 100 times."
I doubt it. I'm happy to review the data, but I bet they're never released for scrutiny. The grad student says nothing about testing lobster movement under 100 different magnetic fields. He talks about only two or so different magnetic fields.
Re: GR, Roger wrote, "No doubt he is assuming that part of GR is true. You think that gravity goes faster than light?"
If he assumes GR is true, then he has circularity in his logic and his conclusion is not meaningful. As to my own view, I think 100 years of searching for gravitons without success means they likely do not exist.
Meanwhile, observed data contradicting GR are unpursued. See, e.g., this 1998 story in the Economist documenting data conflicting with GR, apparently without any follow-up by scientists: "A tiny error in the paths of two spacecraft may require the rewriting of some of the laws of physics" (I can circulate full article if interested.)
I can't figure out what Andy means by materialism. If he means the use of physical experiments, then all scientific advances have accepted materialism. If by materialism, he is referring to the distinction between matter and fields, and you think that fields are more fundamental than matter,
then I guess I agree and so would most physicists.
The technology for isolating gravitons does not exist.
What does he mean by "observed data contradicting GR are unpursued"? You can goto to any theoretical physics conference or journal, and find lots of people who think that GR needs to be modified in some way. They would love to find some data that shows GR wrong in some way. No one has found any yet.
Roger wrote, "What do you mean by materialism?"
It is well-defined. It is the doctrine that all phenomena can be explained by matter. Accordingly, materialists reject action-at-a-distance and ignore the double-slit experiment. Materialists insist that magnetism must explain migration, and that gravitons must exist. They believe that evolution must have occurred.
Roger replied, "What do you mean by that [observed data contradicting GR are unpursued]? You can goto to any theoretical physics conference or journal, and find lots of people who think that GR needs to be modified in some way. They would love to find some data that shows GR wrong in some way. No one has found any yet."
There's plenty of data contradicting GR, starting with the article I forwarded last time. The problem is not lack of conflicting data, but an inability to "modify" GR in a sensible way. Unlike Newtonian mechanics, GR is a mathematical system based on two assumptions incapable of easy modification. If you have seen ideas about how to modify the two assumptions underlying GR, I'd love to hear them.
I don't follow. A magnetic field is not considered matter. So explaining migration by means of magnetism is not explaining it with matter.
My recollection is that in Wheeler's big fat GR textbook, maybe a quarter of the book was devoted to various modification of GR that have been proposed.
Actually, there is some data contradicting GR. In the last couple of years, astronomers have become convinced that the expansion of the universe is accelerating. This is contrary to GR, and people think that it must be explained by some modification of GR.