History of Science (Theoretical Physics and Cosmology)
 

We live in a time of great historical events in science and to narrow it down I will limit this thread to theoretical physics and cosmology.

If you included biology, computer science, solid state (condensed matter) physics, the thread would blow up. Porfiry can, should he choose to, create a history of science Forum for more general discussion. But the topic here is just history of the main physical theories and cosmology, which is bad enough already.

What prompts this is happening onto a post by John Baez in Usenet SPR. It is a 3 October post replying to a 30 September post by Lubos Motl, in the thread "Science Fashions and Science Facts"

That whole thread BTW is relevant to the historical situation of theoretical particle physics today----and the bearing that the recent revolution in cosmology has on it.

There has been some concern lately that string theory might fall short of being empirical science because unsupported by experiment and infact not firmly predicting very much that can be used to test it, and also concern that quantum field theory is not mathematically rigorous, so there is growing concern over lack of discipline in particle physics----lack of math rigor, lack of contact with experiment, a kind of disconnected "imaginativeness" that people warn is a break with legitimate hard science tradition. So they were talking and Lubos, the bright young string theorist, said:

"theoretical physics was never a part of mathematics"

and John Baez said:

"Once there were very good theoretical physicists who were also very good mathematicians, like Newton, Leibniz, Laplace, and Gauss. Some even taught in mathematics departments, like Maxwell..."

this is so obvious it blew me away and I thought "this guy is being helped to think clearly by having an historical perspective that the smart young string theorist Lubos seems to lack!" maybe at some points historical perspective really matters.

so lets open a science history thread focused specifically on theoretical physics and cosmology

I will tell you why cosmology in a moment, after I post this

cosmology is providing the challenges
 

there was a revolution in cosmology in 1998
which every survey article I read refers to. this is how the
cosmologists see it. their field became an observational science
(with the HST key project, WMAP, Type IA Supernovae,...all happening around 1998 or shortly thereafter)

So suddenly the "consensus model" cosmos, or the "concordance model" as they sometimes call it, appeared with the well-known
numbers
Hubble parameter 71
spatial flatness----i.e. k = 0 in the Friedmann equation
Cosmo constant (dark energy) 0.73
Dark matter 0.23
Ordinary matter 0.04

If you go to Usenet SPR these days you hear actual CRIES OF ALARM about this. It is actually very funny. The great ship of string theory has encountered the iceberg of the cosmological constant. Also there is nothing in the standard model (otherwise so successful if unrigorous) which predicts Dark Matter. In effect, particle physics is being challenged by general relativity. GR is what gives you cosmology and its numbers---the basic Friedmann model used in cosmology is just a simplified form of the 1915 Einstein GR equation and it says:

the average density of energy in the universe is 0.82 joules per cubic kilometer and particle physics has so far told us about FOUR PERCENT of that with no clue as to what the other 96 percent is about.

Baez also mentioned that GR is mathematically rigorous---it has been worked over by eminent mathematicians for 90 years until there is no fudge (I am loosely paraphrasing Baez, who names the people). This seems to have some bearing on the issues.

Lubos Motl public expressed the wish that some of the "elite" of string theory (presumably Witten, David Gross, Polchinski, Vafa, whatsisname, Susskind?) would get busy and prove that string theory predicts a cosmological constant. At least some positive number, he cried. It can be anything, just not negative! It was a very funny post.

The cosmological constant (dark energy density) which physical theory should predict is 0.6 joules per cubic kilometer.

I sort of think if Maxwell were alive he would be trying to prove this is what it has to be based on whatever theory and if it didnt he'd make a new theory until it did.

But in another corner of the SPR freeforall Leonard Susskind has apparently started evoking the "Anthropic Principle". We dont have to predict the CC is 0.6 joules per cubic km, he says, because it is necessary for life and we are alive so it must be that!
This is to give up the game. The game is to predict stuff like the CC from your theory---not wave your hands and say "We're alive so what is must be!" So another string theorist (maybe its Tom Banks I forget) comes in and takes down the Anthropic Principle.

Anyway the debate is absolutely beautiful and worth learning physics just to follow.

It all has to do, I think, with history. What, traditionally, does a theory have to be to be empirical science? What value is this tradition---suppose we relax the rules (as Lubos has been asking for) and make excuses---well we cant test because the machines arent good enough etc. etc. What happens if you relax the rules?
Well then what research gets public support depends on political decision----if Stalin likes Lysenko then Soviet genetics will be Lysenko genetics and acquired characteristics are inherited----if politics dominates in NSF committees (hypothetical case, you understand), if Loop threatens String, then Loop get frozen out. Under such conditions, hype rules science, and Pseudoscience---belief-systems based on hype and credulity----gets harder and harder to distinguish from the mainstream.

So there is more reason these days, I think, to go back to history and look at what is special about this endeavor: a self-disciplining voluntary enterprise based in largely in civil society with traditional standards which somehow need to raised again, or so it would seem