Every once in a while, as regular readers know, I write about quantum mechanics. I don't write as an authority -- I was a solid "C" student in an adult-education course in calculus about 20 years ago and will never make a pretense to understand particle physics. The sphere diagrammed in this image has something to do with quantum theory, and something to do with calculus. And that is all I can tell you about it! But quantum mechanics is relevant to many of the philosophical questions in which I have a vested interest in my capacity as a thinking human. So I do need to keep struggling with it. I recently came across an interpretation I had not heard before: the transactional interpretation. By way of preface: The mainline interpretation is known simply as "Copenhagen" after a period in the mid 1920s when Heisenberg worked as assistant to Bohr at the University of Copenhagen. The Copenhagen view accepts the complementarity of wave and particle readings, acce...
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I simply want this to be expounded once in this blog. I've alluded to the double slit experiment in some of my recent remarks on quantum theory and its philosophical overlay, and I even pasted an image of one hypothetical result of the experiment onto my most recent such discussion. But for this once I'll be explicit. Imagine that electrons, or photons, are little tiny particles, as Democritus might have imagined. Imagine shooting them (in Chicago-movie machine-gun fashion) at a wall that had two parallel slits in it, and that there is a screen behind the wall, such that each particle that gets through the slit leaves a mark on the screen. What would you expect to see on the other side of that wall? You'd likely expect to see marks directly behind each slit, corresponding top the shape and size of the split. Some portion of the screen that lay between the two slits would presumably be left unmarked. That's not what happens. Consider light first. Thomas Young d...
I discussed Quantum Bayesian theory here about three weeks ago. But now that I know what to look for, it has become easier to find more about it, so I come back to it. Early this year, the William & Mary blog ran an interview with Hans Christian von Baeyer, who believes that QB-ism (which he pronounces "cubism" as in Picasso) is nothing less than the "future of physics." He regrets that advocates of QBism have yet to get it into physics textbooks. But there are "hundreds of articles and conference proceedings" that deal with it, so he is hoping admission into the canon, with the dozen or so older interpretations of quantum mechanics, will come soon. Von Baeyer also makes reference to "an excellent article" that was added to the Stanford Encyclopedia of Philosophy in December 2016. So, after finishing up the interview, I went there. The actual title of that article is evidence that this is an appropriate thing to be discussing in a blo...
"The great theories of 20th century physics -- relativity, quantum theory, and the Standard Model [of subatomic particles] -- represent the highest achievements of physical science. They have beautiful mathematical expressions that result in precise predictions for experiments, which have been confirmed in many cases to great accuracy. And yet I have just argued that nothing along the lines of these theories can serve as a fundamental theory. This is an audacious claim in the light of their success." Another quote from the Lee Smolin book. I like the audacity. In fact, if I understand him at all, Smolin has delivered me from an intellectual cul de sac in which I have been stuck. I've been unable to accept the Big Bang as an absolute cosmic beginning, given the huge something-from-nothing stumbling block. So I have said -- in this blog and elsewhere -- that I believe some patching up of the old Steady State theory will again have its innings. But the advocates of ...