Do you mean the many-worlds interpretation of quantum mechanics?
Look, the reason why I seem frustrated about this argument is that what you're saying is not far off from the usual critique in economics, maybe of most social sciences. It is fair game to criticize a model of human behaviour, formalized or not, by either dispelling its assumptions or show it is empirically falsifiable.
I don't have time to listen to the whole podcast you linked to, but I read one of the articles written by this Dr. Denniss, on the solvency of Australia's social security system:
Read: “The purpose of the report is to get you worried about rising costs. If the report pointed out that budget revenue was likely to rise faster than budget outlays, people wouldn’t be scared.”
This is a valid critique, and I think accuses the model of the "Ricardian equivalence" assumption too often sneaked into a macro model for tractability. I don't know if it's any good, but it is valid.
Similarly, from the paper you linked to about the Becker-Murphy model of rational addiction:
Let me make another analogy. Assume someone invented a machine that is used in surgeries and can automate some precise procedures doctors cannot follow perfectly. Then, while the machine is successful in some trials, in others an unknown bug will mess up the procedure and almost kill patients.
The range of common-sense solutions span a regulatory agency not allowing the machine to be used until it is more successful, the company creating the machine getting sued for malpractice, up to banning the machine's production altogether.
If orthodox economics is the machine, what you're arguing isn't analogous to any of those "common-sense solutions." What you're arguing is "this machine should not be for sale, but because medicine is not a science like physics this incident should have us reconsider using leeches."
Methodology is hard. It seems easy at first because there are people who make it sound easy, but nine times out of ten they don't understand it either. If you cannot argue methodology correctly, all you're doing is throwing non sequiturs and crowding out legitimate arguments.
For the record, the cost-benefit/welfare analysis style of thinking, so often mentioned in the articles you linked to, isn't very popular in economics these days: for the past two decades most work has been on causal inference, and that kind of analysis has seeped into the policy world (the World Bank funds a lot of randomized controlled trials, for example). There are serious problems with how slow dissemination can be, and how practitioners are not communicating with academics. Why not focus on this instead of "calculus in economics?"
