I’ve updated this post since this paper is now published in Foundations of Physics, at this link: https://link.springer.com/article/10.1007%2Fs10701-020-00336-6
A recent paper by Frauchiger and Renner has brought to light a serious problem with conventional approaches to quantum theory, by deriving a contradiction using those approaches. In FR Paradox Kastner 10.17.19 I argue that the paradox shows that quantum theory leads to absurdities and inconsistencies unless there is a clear physical criterion for ‘measurement’. This is a draft, so comments welcome!
Transactional Interpretation 