Tuesday, September 08, 2009

Where Have You Gone, Isaac Newton?


This is the article I mentioned in an earlier heated discussion over global warming.

The author hypothesizes a Newtonian vs. Einsteinian paradigm for science. One, he says, is cautiously empirical; the other, freely theory- and model-based.

He quotes Einstein, who insists (contra Kant, I think) that "theories are 'free creations of the human mind.'"

The article is, I think, worth noting, but those better versed in the philosophy of science should have the final say.



2 comments:

lastchancetosee said...

Interesting article.

Before I adress his main point I have to first correct some (a lot) of the examples he cites as proof for his ideas. So, in defense of my fellow physicists:



1) "particles travel any [...] paths simultaneously



Not a supposition but demonstrable fact. A simple version of the relevant experiment was actually one I did in school - it's that simple.



2) "randomly pop into and out of existence"



Dito. These particles, while themselves unobservable, have measurable effects. Unfortunately not something you can do at school ;)



3) "They enjoy treating the entire universe as a "fluctuation of the vacuum" [...]"



Err, no, they don't (at least as far as I know). Vacuum fluctuations play an important role in quantum field theory, but our universe is not one.



4) "The fabric of this strange universe is a non-entity called "spacetime, which expands, curves [...]"



Again, a consequence of relativity and established fact.

That, too, is quite simple. I guess you're OK with concepts like space and time? Well, since relativity we know that the two are interrelated and so were replaced by the more generalized concept of space-time. It is the "fabric" of the universe the same way space and time were (or weren't).

It doesn't attend yoga classes thought, but I might be misinformed on that one.



5) "travel backwards in time"



Here it get's interesting. I'm not sure whether or not this was experimentally verified, but it is predicted by theories that are. More on this concept further down.



6) "a hologram"



I'm unfamiliar with that hypothesis and therfore can't comment on this.



7) twenty-six dimensions



Actually, I'm with the author on this one. It's hard to take string theory seriously. Again more on this further down.



I think those are all the examples the author cites. If that is the basis for his claim that physics has degenerated into pseudo-science, he badly needs to find himself some new examples.

lastchancetosee said...

*Post split due to size limitations.*

Now, on to the true examples of non-evidence-based physics:



A big part of this is just stuff that is predicted (if yet unverified) by otherwise by evidence well-supported theories (for example: quantum electro dynamics predicted the value of the magnetic moment of the electron with incredible precision long before we were actually able to measure that accurately. It still stands as the theory with the most numerically accurate predictions, ever. Another example is antimatter: This was predicted by Paul Dirac in 1928 and discovered by Carl Anderson in 1932).

Far from a flaw, this is actually exactly what you'd expect from a good theory, not only to explain what you have measured, but also to correctly predict what you will measure.



Which brings us to the point where I (partly) agree with the author: The "free-floating" hypothesis (like string theory).

Let me first explain where these come from:

The problem right now in particle physics is that the theory is much to far ahead fo the experiment. A lot is tested now or can be tested soon, but a lot is happening under conditions of such high energies as to be completely untouchable by current-state experimental setups (and will continue to be so for a long, long time).

So the only criteria we have is thatthe hypothesis has to explain what is already explained and may not conflict with itself. If those criteria are met than the hypothesis is valid and you can try and test it's predictions against reality. Since we often can't do this, the hypothesis remains sort of in limbo: You may think you have explained something, but you can't be sure if your explanation is right.

I think most particle physicists know that.



The example the author cites, string theory, has other problems that I don't want to go into at this point.



To summarize: A lot of what happens in theoretical particle physics (note the emphasis) these days is highly conjectural.

To conclude from this that physics is decending into pseudo-science is incorrect at best, especially if the examples you cite to prop up your theory are almost all indicative of nothing of the sort.





Random sidenotes:

"theory of everything"

I don't think this refers to what the author thinks it refers to. It most probably refers to the Grand Unified Theory, a theory that unites 3 (hopefully soon all four) basic forces into one fundamental force. At least that is the only context I have heard this. Again, this is much less conjectural than the author makes out.

I agree with him on the megalomania part, though. People should learn from history: At the beginning of the 20th century scientists also thought they had explained almost everything. Then came quantum mechanics and relativity and changed everthing.



"Unfortunately, their stories about make-believe worlds are of no value to people living in the actual world."



This pisses me off. People think the same about relativity. And yet: Does the term "atomic bomb" mean anything to the author?

"... nothing intellectually compelling or challenging.. bald assertions coupled to superstition... woefully pathetic"