The scientific method is based on a logical fallacy

Newton's law of gravity does not predict any expansion for the universe. You're probably thinking of Einstein's theory of general relativity. Einstein originally introduced a cosmological constant in his theory to keep it from predicting a contracting universe, believing at the time that observation indicated a static universe. Hubble's discovery of the expanding universe caused an adjustment to this cosmological constant. It is a measured value and is not predicted by theory. If you're still thinking of the expansion of the universe then you should be referencing dark energy, which is the postulated explanation for the accelerating expansion of the universe. Dark matter is the postulated explanation for the force keeping the outer reaches of rotating galaxies from flying off due to centrifugal force. Again, if you're talking about Newton's law of gravity as expressed by his famous equation and its derivatives, as an approximation for sub-relativistic velocities and masses it is unlikely to ever be overturned. Too many space probes have traveled too accurately too far for it to ever be overturned.If you're instead talking about Einstein's general theory of relativity, it has been verified nine ways from Sunday, but our deepening understanding of the universe could easily lead to modifications of Einstein's theory. Einstein's theory predicts the measured bending of light around the sun, and it predicts the precession in the orbit of Mercury, and the fact of these rigorous mathematical validations makes it unlikely for the theory to ever be completely tossed aside. The most that might happen is that it is found to be incomplete. For example, some cosmologists are investigating whether gravity works differently than Einstein's general theory predicts over cosmological distances. It is an odd question to ask if the theory of gravity has been falsified. You're again not clear about whether your talking about Newton or Einstein. Certainly Newton has been falsified for relativistic speeds and masses, but his gravitational equations work just fine in most circumstances. There are some cases where taking relativistic effects into account yields measurable increases in accuracy, for example slingshotting around Jupiter for a velocity boost, and there's Mercury's precession, but for the most part we use Newton inside the solar system.Einstein's general theory of relativity hasn't been falsified, either, and it is unlikely to be so. As mentioned above, it is more likely that it is incomplete. We already know that the gravitation of Einstein's general theory can't be unified with the other three forces or with the quantum level, so physicists expect that there is much new physics waiting to be discovered. But Einsteinian general relativity can never be completely falsified because of the astounding number of correct predictions it has already made. There's a current set of experiments confirming that spinning masses also have Einsteinian gravitational effects, so the steady stream of correct predictions over the years continues.In other words, the strength and endurance of a theory lies in its history of successful predictions. The more correct predictions a theory makes the stronger it becomes and the more difficult to falsify, not because it is more true the more it makes correct predictions, but because the more it makes correct predictions the more likely it is an accurate representation of reality.Correct predictions are unlikely to derive from an erroneous theory. For example, the theory of the luminiferous aether predicted that the speed of light would be less in the direction of motion than in an orthogonal direction. One of the great achievements of the late nineteenth century was the Michelson/Morley experiment falsifying the theory of the luminiferous aether. The weakness of this theory is represented by it's inability to make successful predictions.A strategy of developing theories that explain existing phenomena and that make predictions about future phenomena is what should be followed by all who hope to add to our scientific knowledge.--Percy

That's where dark matter comes in. It usually exists in a halo around the galaxy, and not very much within the body of the galaxy itself, and this keeps the rotating matter in the galaxy's outer reaches from flying off. The existence of dark matter has been verified because we can detect the bending of light due to its gravitation field, but other than this we can only speculate about its nature. A law is just a theory, which itself is an interpretational framework for thinking about phenomena. Theories that lend themselves to strict mathematical expression have a tendency to receive the "law" label, but this isn't a strict rule. Like most language, which theories receive the "law" label defies any strict categorization. Relativity is very mathematical, but perhaps because the math and the concepts themselves are largely inaccessible to laypeople both the special and general versions receive the appellation of theory. On the other hand, something so loosely true as "Computer power will double every 18 months" receives the label of Moore's Law. Go figure. Language is fickle.Regarding your questions about the falsification of theories, thinking more about this I'm hard put to think of any theories that have been falsified. Theories only become theories after a lengthy and extended period of validation and replication. I think it is much more the case that hypotheses get falsified. Given their prior successful validation, theories are much more likely to be modified or extended rather than replaced.Science includes the ever-important property of tentativity, meaning that we never hold any knowledge as certain, but this does mean that science is just one revolution after another, each generation throwing out the theories of the previous. It just can't work that way, because science is tied through evidence to the real world, and the laws of the real world do not change from one scientific generation to the next. Science is an accumulative process, one of endless conceptual deepening and refinement.--Percy

I think it might be best if you tried thinking this one through on your own, but I'll provide a couple hints. First, Cavediver and NosyNed do not see their statements as being in disagreement. Second, two different people are most unlikely to ever express the same concept in identical language, or even from the same perspective. Yes, I'd agree that creationists have this problem, but doesn't really apply to the case of Newtonian physics versus Einsteinian general relativity. Both have an extremely lengthy pedigree of validated tests. We already know the ways in which Newtonian physics is incomplete because Einstein's theories cover those areas.We strongly suspect that Einstein's theories will prove to be incomplete, but given that the validations have already taken place it's impossible to imagine how Einstein's theories could actually be wrong about the precession of Mercury's orbit or the deflection of light by gravity or the relativistic effects of spinning masses to the accuracy available today.We hope we'll continue to add to our knowledge, but we can't say today whether that means that Einstein's theories will be extended, modified, or perhaps become embedded inside a future theory of greater explanatory power, the way Newtonian physics is now embedded within Einsteinian theory.--Percy

Dark matter has been verified by its effect on both the structure of galaxies and on the path of light passing nearby. There are two popular proposals for the nature of dark matter, MACHOs (MAssive Compact Halo Objects) and WIMPs (Weakly Interactive Massive Particles). WIMPs seem to have the upper hand in scientific circles these days, but who knows how it will come out.The possibility you mention that the phenomena currently interpreted as caused by dark matter is actually due to some other new physics cannot be dismissed out of hand, but it isn't being seriously entertained at present. If as research into dark matter continues the current hypotheses of MACHOs and/or WIMPs do not hold up then you can expect your own preferred alternative to receive more attention. The history of science does reveal a certain amount of inertia that causes newly discovered phenomena to be interpreted within the framework of older theories. This was certainly true of Einsteinian general relativity, where many physicists insisted on trying to shoehorn Einsteinian effects into a Newtonian framework. Such conservative behavior is just part of human nature.I don't myself see any analogy with creationism, largely because creationism is not based upon observation and study of natural phenomenon, and because unlike Newtonian physics as it was replaced by Einsteinian physics it has no history of validated predictions with replication.--Percy

Cavediver and NosyNed were focused on two different theories, primarily because when you started out you weren't clear whether you were talking about Newtonian or Einsteinian physics, but they were making the identical point about falsification. Einsteinian physics has a record of successful predictions that have been replicated many times, and this record of success is part of history. There's no way to change the past that I can imagine. Creationism has no record of successful predictions, and of course no replications since there's no successful experiments to replicate, so it is very easy to imagine the falsification of Creationism, and of course it's already been falsified many times even as just a working hypothesis.But I sense we're drifting off the topic now, which is the scientific method. You seemed to be interested in understanding falsification at first, a key part of the scientific method (verifying hypotheses), but you seem to be focusing increasing amounts of attention on defenses of creationism, and I don't know why since no one else is mentioning creationism except you. If you're truly interested in falsification, I think that's much more on topic.--Percy

I would agree with that. What we have at present concerning dark matter are hypotheses.Science operates under the presupposition that we do not know everything. This means that our theories must always be considered potentially incomplete, possibly even wrong, since there's always the possibility of discovering some new phenomena that our current theories do not explain. When new phenomena are discovered there is always a period of exploration of how well they fit with existing theory. If existing theory is found to be incomplete then that is no surprise since we were already operating under the presupposition that existing theories are likely incomplete.If existing theory is actually discovered to be wrong then that would be quite an indictment of the scientific process since it would mean that insufficient testing and replication of tests of the theory were performed. I'm trying to think of a theory that fits this category, and I think Freud's id/ego/superego theories might qualify. Certainly that very early period of the science of psychoanalysis was dominated far more by personality than science.--Percy

You're advancing your own false premises so you can knock them down? What's the point?The behavior of light passing by galaxies and the structures of galaxies themselves can be explained by the presence of a halo of matter surrounding galaxies that aside from gravitational effects we have not so far been able to detect. Other explanations are possible but not being actively explored at this time that I'm aware of.Similar to the situation with dark matter, Neptune was discovered by way of its gravitational effects on Uranus. Noting that with Neptune we trained our telescopes on the spot and found it but with dark matter we see nothing, you believe there's actually nothing there and that the hypothesized dark matter is a chimera and general relativity wrong.Maybe you're right, who knows, but the usual process of science is to do the research first, then arrive at the conclusions after the evidence is in. You seem to want to reach the conclusions first, discard the theory, then just forget about the research.Don't forget that at present general relativity fits all the data. Given the huge numbers of particles that pass through the earth every day almost completely undetected, such as neutrinos, and given that we haven't discovered all the particles predicted by the standard model, such as the Higgs Boson which is thought to be omnipresent and mediate the gravitational force despite the fact that we haven't detected it yet, it is no wonder that the cosmological and particle physics communities do not have much of a problem with invisible matter.One interesting recent discovery concerning dark matter is a region of dark matter that isn't in a halo around a galaxy, indeed, that isn't even associated with a galaxy. Two galaxies collided, and the momentum of their halos of dark matter caused the dark matter to end up in one location, and the galaxies in another. This would argue against the need for modifications to general relativity. Yes, of course, dark matter is itself a hypothesis.--PercyEdited by Percy, : Fix grammar.

The distribution of matter in the universe is measured, not derived from theory. Are you perhaps thinking of efforts to match variations in the CMBR to the distribution of matter? Anomalies such as Pioneer 10 and the structure of rotating galaxies are being studied. Science wouldn't be very interesting if we'd already figured everything out. Scientists are delighted to have problems like these. Reputations are made not by adding decimal places to existing knowledge but by discovering new science. You seem to see anomalies as indicative of something rotten at the core of scientific practice, but there has never been a time when there were not scientific anomalies. There's never been a period in science when all known phenomena were explained by existing theory.Wouldn't throwing out GR be grossly premature? It seems strange that anyone would push for discarding so successful a theory while options consistent with GR exist and while research is still ongoing. Discarding GR would put you in a somewhat awkward position if, as is one of the likely possibilities, GR is eventually found consistent with the anomalies, or perhaps requires modest modification.GR currently makes the most accurate predictions, such as with slingshotting around Jupiter and with the precession in the orbit of Mercury. As a practical matter you cannot discard GR because naturally astrophysicists would continue to use it, as there is at present no alternative and it explains the vast majority of phenomena. What sense would it make to designate GR falsified and discarded while it was still predominate and making successful predictions. I think we'd all like you to stay focused on the topic. Again, I think we'd all like you to stay focused on the topic.--Percy

I mentioned this back in Message 59, thanks for providing the references.--Percy