Monday, April 12, 2010

Leonard Susskind on Special Relativity


I just discovered this You Tube video by Leonard Susskind the other day, and wish to share its excellence. Although I have many professional disagreements with "Lenny" on other non-basic subjects, especially regarding "The Anthropic Principle", or as Stephen Jay Gould called it: "Ships were made to house barnacles" theory, he is nevertheless a magnificent teacher on the basic important bits, as you will see:

6 comments:

Steven Colyer said...

Hopefully this blogpost will surprise some of you who think I dislike Lenny. I don't dislike him, I love thinkers and Scientists. I am however discouraged at his personal attacks ala Lubos on Lee Smolin. It's unnecessary and beneath human dignity, and politically motivated as well. For example,from the Wiki link in the blogpost:

In 2006, Susskind criticized Lee Smolin as a "mid-level theoretical physicist" whose "popular book-writing activities and the related promotional hustling have given him a platform high above that merited by his physics accomplishments."

Was that necessary?!

The original article by Susskind can be found by clicking here. He attacks Princeton and Wolfgang Pauli as well, so you're in good company, Lee.

Jérôme CHAUVET said...

Dear Steven,

I do not understand why, if so excellent, his anthropic principle should be so crackpottic. If he is so excellent, he must know what he has stated this for, no?...

The anthropic principle does not solve anything, true, but this is a potential paradigm with which to build your reflection. As a biologist, I understand what this claim is aiming at because it directly refers to Darwin's natural selection principle: Should we think our universe being the only one possible, or are there many possible ones and we are just lucky to observe it the way we observe it because of a particular selection process which made it and us the way we are. What L. Susskind is pointing out is what sort of axioms should one take into account when theorizing the universe as an emergent structure. The fact that his reflection yields no technical answer does not mean it makes no sense, as before inventing anything, one has to make many fundamental choices, particularly : What sort of concepts are going to lead to solving technical issues.

Susskind's statement is a concept... I don't understand why one should mock someone proposing philosophical conceptions.

Regards,

Jérôme CHAUVET said...

Concerning Susskind's attacks towards Smolin, both are playing in the same game, so he is just competing... Maybe is he envious regarding Lee's popularity. But Lee Smolin is a nice person, and I prefer Lee Smolin anyway, as I think nice persons must always win the game : nice persons have nice ideas, because they create things with respect to what others are waiting for.

Best,

Steven Colyer said...

Lee's good point is that if something isn't provable nor is it falsifiable, can we then call it Science?

Lee says No! I agree. Moving on..

Yes, they are players in the "game" but "no" I don't think envy has anything to do with it because as "The Father of Superstring Theory" I would say Len is no less famous within the community, and his books seem to sell as well as Lee's to the general public.

It might be something as simple as Len's from the South Bronx and Lee's from Brooklyn. Watching New Yorkers duke it out is like a catfight. You can watch, but if you try to get involved then woe to you, it will not end well.

But in any event I do not care. It's just unfortunate all around. And so, moving on ...

I reject The Anthopic Principles, both the weak and the strong, because of their tautological nature. Also because they've gone too far into the mathematical realm which risks losing any connection whatsoever with the real world.

Anthropic is like a big blanket. You can't prove it wrong, you can't prove it right, so it comforts mathematicians.

Engineers like specific problems to solve. Physicists want simple rules (formulas) they can then give to the Engineers. Mathematicians want to generalize. Anthropic is the ultimate generalization. It helps no one understand the real world, alas.

Fortunately for superstring theorists the Anthropics are in the minority (I think), so if superstrings are to succeed then David Gross at Kavli and the Princeton-IAS boys et. al. recognize that and are on the job.

Peter G Kinnon said...

Susskind and Smolin are both woolly thinkers, a prominent characteristic of theoretical physicists when not operating in the simpler language of mathematics.

The "fine tuning" of the observed physical constants that critically permit the existence of biology have been discussed by many, a particularly exhaustive treatment having been presented by Barrow & Tipler in "The Cosmological Anthropic Principle"

In chapter 11 of my own book "Unusual Perspectives" this kind of analysis is extended "downstream" to provide, within the context of the unique properties and timely abundancies of the chemical elements, very compelling evidence of further "fine tuning" that not only allows, but essentially makes inevitable the observed exponential development of technology for which our particular species has been the vehicle.

Several ways to account for this indisputable "fine tuning" have been proposed.

1. Creationists have seized upon the evidence to support the idea of a deity or "higher intelligence". As indicated above, I suspect that anthropocentrism alone promotes this kind of interpretation. Adding any kind of "higher intelligence", of course, makes for a very extravagant hypothesis. But it is not disprovable.

2. The existence of a multiplicity of universes, perhaps infinite, each with a different set of physical properties. So one of them had to get lucky, right? This is favoured by many of those theoretical physicists who choose not to just stick their heads in the sand to avoid the implications of interpretation 1. Again, can be neither proved or disproved but even more extravagant.

3. The "anthropic cosmological principle", the non-superstitious version of which seems to boil down to "we're here, because we're here, because we're here.
By virtue of its tautologous nature it is not disprovable.

4. The Everett "many worlds" model, inspired by the "Schrodinger's cat" kind of dilemma that arises from quantum mechanics. This essentially can be viewed as continual bifurcations of our universe such that, in the instance of the cat, in one of the resulting universes is is dead and in the other, alive. The bifurcations, of course, result in a multiplicity of "parallel universes. Again, very extravagant but probably not disprovable,

5. A far more economical model, derived from consideration of the gross evolutionary patterns that we observe in biology and, more recently technology, is presented in "Unusual Perspectives" the electronic edition of which is available for free download from the eponymous website.

To properly appreciate the reasoning therein, however, it is very important to first discard the anthropocentric mind-set that leads to problems with concepts such as "purpose" and "design". They, like "gods", "intelligence" and "free-will" are merely products of our own mental environments that preclude objectivity.

Steven Colyer said...

Hi, Peter, thanks for writing. That was a great reply in that there are many things I agree with and of course much to ponder. I've added your book (thanks for making it available on-line) to my To-Read list and look forward to reading it once other priorities are settled.

I have studied Anthropic in some detail (therefore I learned early on who Barrow & Tipler were ... you don't get far into Anthropic without meeting up with them) which is why I came to my tautology conclusion. I have to agree with Smolin that since it's not provable/disprovable it should not be considered Science. Science is what I'm into. Perhaps in 100 years we'll have the technology to explore it in more detail, or technology will render it obvious via the Sherlock Holmesian approach. In my lifetime however there are other issues that are solvable and that's where I choose to focus my attention.

I think Susskind is a salesman for the ages. A very funny man as well. Smart as a whip. Not necessarily right.