Jamesian Philosophy Refreshed

Sabine Hossenfelder, a theoretical physicist (she did a doctoral thesis on black hole production) and a prolific science popularizer, discussed in her blog recently whether physicists have any good reason to posit the existence of "dark energy." About the turn of the millennium, physicists determined that the expansion of the universe is accelerating. They didn't know why, so they proposed a "dark (otherwise unobservable) energy" that was driving this acceleration. There is a key paper by Chevalier and Polarski in the International Journal of Modern Physics  from 2001.   But the simple idea, once postulated, didn't stay simple.  Theorists were soon explaining why dark energy has to be understood to be "evolving," and competing scenarios for that evolution themselves evolved.   Now quite recently, a group of mathematicians have looked at the numbers and have decided that this work may all have been a wild goose chase.  There need be no dark energy ...

Long time readers of this blog will recognize the name Sabine Hossenfelder. I have referred to her and ideas she has championed with some regularity. I am sad to report that attempts have been made to silence Dr Hossenfelder and happy to add that she has resisted them, and appears likely to continue saying what she means for some time to come.   Hossenfelder has a doctorate in theoretical physics from Goethe University Frankfurt.  Her dissertation, in 2003, looked at microscopic black-hole production. Lately, she has acquired some prominence as a nemesis of what she considers bullshit in the world of science and of physics in particular.  She believes that physics as an academic field of research has guided itself into a dead end, where bullshit creation is incentivized. Recently, for example, a distinguished scientific journal published a paper about the mathematical modeling of 'warp drive' as a way to get near and/or past the speed of light. The paper was then pic...

I admire those scientists -- I mean actual credentialed working scientists -- who deign to spend a lot of time explaining science to layfolks like me. They are a differentiated bunch. Examples that come to mind are: Neil deGrasse Tyson, Lawrence Krauss, Michael Polanyi, and -- my personal favorite -- Sabine Hossenfelder.  This must be roughly the tenth time she has inspired a post in this humble blog.  Let me introduce her credentials. Hossenfelder has a Ph.D. from Goethe University Frankfurt, for which she wrote a thesis on "Black Hole Relics in Large Extra Dimensions."  That will give a flavor of such of her work as is aimed at peers.  She is also a fellow blogger. In a recent post on one of those blogs she argues that humans have been lying to ourselves about plastic. She thinks that the stuff is building up and may well prove disastrous for us.  To this point she cites the OECD, which says that the use of plastics doubled globally in the period 2000 to 2019...

Quantum mechanics seems a little bit less weird and counter-intuitive now than it did before November. Since around last Thanksgiving a scientific paper has been making the rounds, and gradually it has become grist for science journalists Now the idea has come to you, via my humble blog. The Cheshire cat and its smile do not actually separate in the quantum world.  It has long been thought that certain subatomic particles can be in one place and that certain of their properties can be in another. Ah, what a mystical idea! what a contribution to the reputation of quantum mechanics for sheer weirdness!  Indeed, no less a physicist than Albert Einstein objected to the "spooky stuff" in quantum mechanics in its early development.  Einstein wasn't wrong. There is spooky stuff and it does make quantum physics look like something less-than-ultimate, something that will be explained by something else deeper as thought progresses. If Einstein turns out to be right about that, thou...

  ... we're talking about 6G already? Some of us still have our ears ringing from all the talk that accompanied the advent of 5G! Indeed, in some quarters 5G was blamed for the advent of Covid-19. That was nonsense, of course, but it reflected the shock of the new. Now we must be prepared for the shock of the newer, Sabine Hossenfelder, a prominent physicist, has spoken to this point recently, specifically speaking to the matter of frequency. SixG will give us much lower latency and capacity. No more frustrated waiting for something or other to finish buffering. (Isn't that something you do to a floor?) And it will be the higher frequencies that will allow this.   The problem with that high frequency is that such signals are easily blocked. Researchers think they've found a way around this, but the results of their experiments so far are not impressive.  Six G isn't supposed to be rolled out until 2030 anyway, so they have time to work out the kinks.    ...

Now THAT is a neat phrase. "Causal dynamical triangulation." It is apparently a theory on the cutting edge of subatomic physics. There's a wikipedia article under that title but it doesn't really explain the matter for dense folks like me. What I do understand, though, is that efforts continue to render Einstein's understanding of gravity consistent with quantum mechanics. This requires the quantization of gravity, something that was worked out in principle in the 1960s. BUT ... the so-called "naive" quantum gravity developed by Feynman etc. can't be the last word. Physicists are agreed it can only be an approximation. How to get the rest of the way there is the continuing subject for debate. And THAT is here CDT comes in. What intrigues me is that, as Sabine Hossenfelder has written, CDT requires that we treat space and time differently, "which Einstein taught us not to do." So the idea is to keep Einstein's notion of gra...

Sabine Hossenfelder has a fascinating post in her blog about the role of "heroes" in science writing/popularization. People writing about the sciences want to tell stories, because they presume that the people reading their stuff like learning stories: and they are likely right because the human mind is structured to take information in that way. So ... here's a simple story. Individual A confronted difficult problem B at a certain moment in A's life, and in a specific context got an inspiration. He tested out the inspiration and -- ta da!  -- it solved the problem, making him/her a hero.  Insert memorable details involving botany or zoology along the way. In this manner a writer/popularizer conveys to his broad not-PhD-holding audience what problem B was, how it was solved, and thus what are the basic scientific ideas involved. Let's leave Newton's apple out of this. There's a much more recent example that involves pigeon shit. What is now called Co...