On 10/28/2022 8:55 PM, Bruce Kellett wrote:
On Sat, Oct 29, 2022 at 1:42 PM Brent Meeker <[email protected]> wrote:On 10/28/2022 6:43 PM, Bruce Kellett wrote:Look, "ad hoc" is frequently bandied about as a fatal flaw in any theory. Just as Putin waves about the nuclear threat: this is just to intimidate the opposition, it doesn't mean anything more. Any theory has ad hoc elements, or else it would not be of any value in explaining our experience. There is always a theoretical part, and then a collection of elements that serve to relate the theory to observation. Everything is ultimately ad hoc, because it is for the particular purpose of explaining observation.I think you've stretched it's meaning beyond recognition. If every theory that is devised to match experiment is ad hoc then indeed all science is ad hoc...and the better for it. But there is real ad hockery that is deserving of criticism. The real question on the table is what would you take to be not ad hoc; what would be better than "... measurement is then not treated in terms of the fundamental dynamics of the theory." Do you see MWI doing this?No. MWI takes unitary dynamics of the Schrodinger equation to be fundamental. But unitary dynamics and the SE are deterministic, and incompatible with a probabilistic interpretation. So MWI is not going to be able to give a completely satisfactory account of measurement since the outcomes of measurement are inherently probabilistic. So whatever you do in MWI, measurement is not treated in terms of the fundamental dynamics of the theory; there is always some ad hoc element required to make contact with experiment. In that context MWI, is simply engaging in a double standard when it criticizes collapse theories as ad hoc.
I agree with that, since I think collapse or probability is necessary for the theory to work. But I regard it all as one unified theory. As Omnes writes, "QM is a probabilistic theory. So it predicts probabilities."
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