But the key feature of the fundamentally subjective theory called quantum mechanics is that if no questions are being asked, no questions need to be answered. If the objects in our environments aren't asking any questions for us, we don't need to answer them and we don't need to imagine that the world is doing anything else than evolving the probability amplitudes according to the continuous Schrödinger's equation (or equivalent equations in other pictures). In particular, there's no "collapse" if there's no subject asking questions and learning answers! What is often called the "collapse" is the process of learning and it is a fundamentally subjective process. ...He is right about this. MWI has no merit, I have argued.
Philosophy is never a good science. But when it comes to philosophies, many laymen in quantum mechanics – and even people not considered laymen in quantum mechanics by the society or by themselves – often think that "realism" is the right philosophy behind modern science. This viewpoint, based on millions of years of our everyday monkey-like experience, has strengthened by the 250 years of successes of classical physics and it was – unfortunately – energized by Marxism that repeated the untrue equation "science = materialist ideology" many times. Marx, Lenin, and related bastards surely belong among those who have encouraged people to never leave the mental framework of classical physics. But it is "positivism" which is the philosophy that is closest to the founders of the modern science, especially relativity and quantum mechanics.
Positivism says that all reliable knowledge – the truth we are allowed to become fans of – has to boil down to empirical observations and mathematical and logical treatments of such empirical data. It sounds uncontroversial among science types but many of them don't realize how dramatically it differs from the "materialist ideology". In particular, positivism assumes nothing about the "existence of objective reality".
I do agree with Lumo that anyone who advocates MWI (or some of the other peculiar interpretations like Bohm's) has a fundamental misunderstanding of quantum mechanics, and even of what science is all about. There are as misguided as creationists and mystics.
I don't require everyone to adopt my positivist philosophy, but the MWI advocates refuse to even acknowledge that quantum mechanics, as envisioned by Bohr and Heisenberg, is positivist.
As I have also argued, one of the big errors of MWI can be seen in terms of probability, but I disagree somewhat with how Lumo explains it. He says:
After the quantum revolution, we know that all empirical evidence coming from repeated experiments may be summarized as measured probabilities of various outcomes of diverse experiments. Once again, all the empirical knowledge about the physical processes that we have may be formulated as a collection of probabilities. Probabilities are everything we may calculate from quantum mechanics (and from other parts of science, too). So they're surely not a detail.Yes, I agree that probability is important in all of science, because it gives a tool for analyzing repeated experiments. But I do not agree that orthodox quantum mechanics promotes it to being more fundamental than that. Probability is only important in quantum mechanics to the same extent it is important in other sciences.
Orthodox quantum mechanics promotes probabilities to fundamental concepts and uses the standard probability calculus – which existed a long time before quantum mechanics – to give you rules how to verify whether the probabilistic predictions of a theory are right. The basic laws of quantum mechanics are intrinsically probabilistic.
Nate Silver's final prediction was that Pres. Barack Obama had a 92% chance of being reelected, and Peter Norvig said 85-98%. They used reliable scientific methods to forecast the election, but we cannot say whether their probabilities were correct because we cannot directly observe the probability. (For discussion of well these predictions did, see here and here.)
The probabilities do have meaning, even tho they are not directly observable. But the probability has no meaning in MWI, because the MWI advocates would say that Mitt Romney won the election in many of the parallel universes. They could try to argue that Obama won in more universes than Romney, but there is no way to make sense out of that because we cannot see the other universes. Lumo explains this well.
Update: Lumo is enraged by this comment:
Do you consider it ironic to be attacked by some for pointing out the rationality and utility of String theories but attacked by others for pointing out the irrationality and lack of usefulness of MWI?That hit a nerve. String theory has no utility either. It does not explain any observable phenomena, or resolve any theoretical puzzles, or simplify any physics, or have any rational justification. But Lumo is ideologically committed to string theory.