Thanks for a nice article Steve. I’ve always wondered how even very intelligent people can get lost in overly philosophical musings that become totally untethered from reality as we know it. In the end, one must have either the proposition that all external reality is intrinsically solipsistic in some way (which seems rather untenable, as it creates a whole series of a priori problems) or that there really is an external independent reality, in which case mystical “observer effects” are not only misguided but clearly silly. It’s important to recall that in quantum theory an “observer” is merely another element of the larger system — the observer can be, as you note in the double-slit experiment, an electron or photon, or an entire apparatus. The universe was getting along perfectly well for 11.8 billion years before we little apes showed up, which would seem to indicate that the Copenhagen interpretation is simply silly. Equally the many-worlds hypothesis begins to look like a desperate attempt to account for currently-not-understood phenomenon by creating a massive new problem (imagine the trillions upon trillions of new universes that must be created every fraction of a second from activities on Earth alone! Now add in the probability of events elsewhere likewise triggering new universes and you get an absurd outcome). In the end it is always wiser to say that one does not presently understand something than to wander into the weeds of speculation, especially when our tiny ape-brains are not evolved to speculate coherently nor rationally.