On Mon, Jul 28, 2025 at 6:55 PM Brent Meeker <meekerbr...@gmail.com> wrote:
>>>*You've just defined "unmeasured" to mean 50/50 distribution.* >> >> > *>> That's the word I used to describe a single electron if I know nothing >> about its history. If it's not a single electron but there is a beam of >> them and I send many electrons through a Stern–Gerlach magnet then I may >> conclude that whatever the origin of the beam was, it's producing electrons >> in some distribution other than 50-50.* > > > *> Exactly my point. Your 50/50 just an epistemic assumption,**which > measurement may prove wrong. * > *If I'm dealing with a single electron no measurement will ever prove me wrong. * > *> Yet if you take the UP beam from the SG and measure Left/Right the > distribution will be 50/50,* > *Yes but I didn't know it came from the UP beam from a SG, all I knew is that the electron went up, and now that doesn't matter because I've sent that electron to a SG magnet again and I've made a Left/Right measurement so now, although I know if it's left or right, I no longer know anything about up/down except that the probability is 50-50. * > *>> Rather than a definition of measurement I will give you >> something much better, an example. Producing an electron with a known spin >> state, as a piece of magnetized iron does when, thanks to the photoelectric >> effect, it's exposed to circularly polarized light; or when an electron >> passes through a Stern–Gerlach magnet.* > > > *> So which step is the example of measurement, producing an electron with > a known spin state, as when you first measure the magnetized direction of a > piece of iron before ejecting an electron from it, or when the electron > passes thru the SG* > *Both processes produce an electron with a known spin state, so both are a measurement. * > *>>> A bit of iron found in the ground is unlikely to have encountered an >>> SG.* >> >> >> *>>True, but it's not unlikely that something equivalent could have >> occurred. * > > > *That it cooled in the Earth's magnetic field? Is that what you call > equivalent to being separated in an SG?* > *Yes because that leaves a classical record, just like a SG does. * *John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis>* we1 > > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/everything-list/CAJPayv3EcqHsDN7WAD%3DyELUZS1O67HpYTbNuNc36yrhfoUY2Tg%40mail.gmail.com.
