On Saturday, January 11, 2003, at 12:28 PM, Eric Hawthorne wrote:
...Sometimes there is a refinement process which looks a lot like refinement of a computer program, in the sense that more and more of the desired specifications are met. (This is like a series of subsets of a set, with each smaller set converging on the "perfect program," a kind of fixed point for the process. This set-theoretic view has an equivalent formulation in terms of a sequence of branch points, a type of lattice. Cf. "Lattices and Order," by Davey and Priestley, for example.)
This scientific process works pretty well
but is somehow loosy-goosy and unsatisfying. Do theories which replace
other older, now discredited theories, keep getting better and better? Probably yes.
But what is the limit of that? Is there one? Or a limit in each domain about which
we theorize?
Other times science proceeds via substantial paradigm shifts, well-covered by Kuhn of course. In these "knowledgequake" steps, the model of gradual refinement is essentially shifted to one where a change of basis occurs, where the very building blocks are altered. The transition from Ptolemaic to Copernican, for example, or from "humors" to "microorganisms" in medicine.
Both relativity (special and general) and QM basically satisfy the correspondence principle by reducing to the classical theories at low relative speeds, with ordinary falling objects in gravity fields, and with macroscopic objects. (QM does not in the sense that many phenomena--slit and photoelectric, stability of atoms, etc.--have no classical theory. And electronics are all around us and need QM to explain. But QM reduces to classical in various obvious ways.)
Hey, I'm not going to write a free-form essay here on science and the nature of theories, so I'll move on to your next point.
But hold on, most of the scientific revolutions tell us that we had a niceYes, I would, with some caveats.
theory, but were theorizing about a badly-scoped, badly conceptualized idea of what
the "domain" was. A better theory is usually a better set of formal, interacting concepts
which map to a slightly (or greatly) differently defined and scoped external domain than the
last theory mapped to. None of this is very straightforward at all.
For example, would you go out on a limb and say that Einstein's theories are
the "best" (and only "true") way of modelling the aspects of physics he was concerned
with?
His 1905 theory has not been significantly changed, and it has been tested at a wide range of energies (e.g., slowed decay of muons in cosmic showers and accelerators, as one example). And his 1915 theory has been tested in various ways, with gyroscopes in orbit, astrophysical objects, lensing, etc.
However, a new result could always force changes. So far, these have not been needed. (Also, there are new solutions to field equations, new mathematical formalisms like differential forms over standard tensors, and so on. Einstein did not wrap up all problems, even with gravitation. This is why much work was done later, and is still being done.)
And quantum gravity and other "theories of everything" which unite the known forces, are very much up in the air at this time.
So, yes, relativity was the "best" theory and remains so. Is it the "only true" theory for the things it covers? Certainly not.
But science is an evolutionary process, in the evolutionary learning and selection sense. Until something challenges a theory, the theory lives. Until something better comes along...
If so, would you be equally confident that his theories cover "essentiallyNo, and I know of no scientists who claim that a theory is complete and not subject to challenge or replacement by other theories. But theories which appear to be comprehensive in the way QM (and QED and QCD) and relativity are, in their domains, are not lightly challenged. Especially they are not challenge by metapoints about how maybe there are theories which will someday subsume them.
all the important issues" in that domain? Or might someone else, someday, re-conceptualize
a similar but not 100% overlapping domain, and create an even more explanatory
theory of fundamental physics than he came up with? Can we ever say for sure,
until that either happens or doesn't?
No, I don't think this can be said at all. Classical mechanics _is_ what relativity reduces to at speeds found on earth and in laboratories prior to the past century.
You can interpret the history of science in two ways: either we were just really
bad at it back then (in Newton's day) and wouldn't make those kind of mistakes
in our theory formation today,
There's a parsimony issue at work as well. Newton, Laplace, Lagrange, and all of the other classical mechanics folks might have had some inkling that they could incorporate "fudge factors" into their theories, parameters left blank until they could be filled in, but NO EXPERIMENTS and NO OBSERVATIONS needed such fudge factors. Within the accuracy of the experiments, there were no epicycles or orbital corrections needed (not for a long time, not until slight deviations from theory in the orbit of Mercury showed up, as one example).
And this correspondence is not accidental. This is not like saying the theory of epicycles is a limiting case of classical mechanics and gravitation, which it most certainly is not. Let Planck's constant go toward zero and classical mechanics happens. Let v << c and classical mechanics happens.
or you can say, no we're about as good at it as always,It took better tools to see into the regimes where the older theories failed. It will probably take substantial increases in accelerator energies to see into the regimes where quantum gravity is evident...some say that short of probing at Planck scales (of length, energy, time), we will have no way to distinguish amongst competing theories.
maybe a little more refined in method but not much, and we'll continue to get
fundamental scientific revolutions even in areas we see as sacrosanct theory today.
More optimistic folks think we may see some kind of evidence within our lifetimes.
Certainly we are not in a solipsistic situation where new theories are easily formulated and knock off older theories without experimental evidence or unexplained phenomena.
I don't understand your "secret cause of asymmetry in the universe" point. We understand some things about symmetry breaking in particle physics theories, via gauge theories and the like. If you want more than this, you'll have to expand on what you mean here.It is a Koan (kind of). A self-referential, absurd example of a notion that an imbalance in a formal symbol system (the words I'm using, and the quotes) could possibly be the cause of
asymmetry in the physical universe.
Probably not, but I won't get into a debate with you on this.
--Tim May
