Physics Quote of the Day (May 31 - June 6)

"We live of novelty in science. So when you do something new, you have to overcome certain beliefs that it cannot be done, that it's not interesting and so on." Heinrich Rohrer, born 6 June 1933.

"The future cannot be predicted, but futures can be invented. It was man's ability to invent which has made human society what it is." Dennis Gabor, born 5 June 1900.

"The national research effort, upon which so much depends, will remain healthy only so long as there is sound core of disinterested search for new knowledge..." Alan Waterman, born 4 June 1892.

"Too much equipment can be, however, something that hampers scientific development." Georg von Békésy, born 3 June 1899.

""Have we discovered our Galaxy yet?" And I think the answer to this question is "No, not quite". There is plenty of work ahead for the next generation of astronomers." Heather Couper, born 2 June 1949.

"Simplicity is the touchstone in finding new physical laws." Kip Thorne, born 1 June 1940.

"A theory is only as good as its assumptions. If the premises are false, the theory has no real scientific value. The only scientific criterion for judging the validity of a scientific theory is a confrontation with the data of experience." Maurice Allais, born 31 May 1911.

Physics Quote of the Day (May 24 - May 30)

"Scientists tend to resist interdisciplinary inquiries into their own territory. In many instances, such parochialism is founded on the fear that intrusion from other disciplines would compete unfairly for limited financial resources and thus diminish their own opportunity for research." Hannes Alfvén, born 30 May 1908.

"(Physics) is about understanding! Understanding the world!" Peter Higgs, born 29 May 1929.

"Only by doing the best we can with the very best that an era offers, do we find the way to do better in the future." Frank Drake, born 28 May 1930.

"Good physics can be done if we have a good shop. ... Given a good shop and good measurement equipment a sound physicist can do wonderful work." W.W.Hansen, born 27 May 1909.

"When you're getting ready to launch into space, you're sitting on a big explosion waiting to happen." Sally Ride, born 26 May 1951.

"The problem of transmitting scientific knowledge is a very difficult business." Jack Steinberger, born 25 May 1921.

"Every failure is a step to success." William Whewell, born 24 May 1794.

Physics Quote of the Day (May 17 - May 23)

"Science is a field which grows continuously with ever expanding frontiers. Further, it is truly international in scope. Any particular advance has been preceded by the contributions of those from many lands who have set firm foundations for further developments." John Bardeen, born 23 May 1908.

"For the mere purpose of entertainment and the excitement of wonder, a display of brilliant electric experiments, even when performed in the most promiscuous and confused order, never fail to afford ample gratification to the curiosity. The studious observer, however, whose business is to inquire into the true beauties of the science, requires the most judicious arrangement of the phenomena that can possibly be devised, in order to facilitate his acquaintance with them, and with the laws by which they are displayed and associated with each other." William Sturgeon, born 22 May 1783.

"(Fresh and deep) ideas, after all, can arise only in discussion, in the face of objections, only if there is a potential possibility of expressing not only true, but also dubious ideas." Andrei Sakharov, born 21 May 1921.

"I think there is a need for something completely new. Something that is too different, too unexpected, to be accepted as yet." Anton Zeilinger, born 20 May 1945.

"...a number of current theoretical explorations will turn out to be passing fancies..." Abraham Pais, born 19 May 1918.

"The most essential characteristic of scientific technique is that it proceeds from experiment, not from tradition. The experimental habit of mind is a difficult one for most people to maintain ; indeed, the science of one generation has already become the tradition of the next..." Bertrand Russell, born 18 May 1872.

"I knew my purpose well and clear: to show how Nature behaves without cluttering its beauty with abtruse mathematics. Why cloud the charm of a Chladni plate with a Bessel function?" Julius Sumner Miller, born 17 May 1909.

Physics Quote of the Day (May 10 - May 16)

"A philosopher is a person who knows less and less about more and more, until he knows nothing about everything.
A scientist is a person who knows more and more about less and less, until he knows everything about nothing." John Ziman, born 16 May 1925.

"An ordinary mistake is one that leads to a dead end, while a profound mistake is one that leads to progress. Anyone can make an ordinary mistake, but it takes a genius to make a profound mistake." Frank Wilczek, born 15 May 1951.

"I think it is a sad reflection on our civilisation that while we can and do measure the temperature in the atmosphere of Venus, we do not know what goes on inside our souffles." Nicholas Kurti, born 14 May 1908.

"A theory can never be proven absolutely true, therefore there is no end to scientific endeavor." Kristine Larsen, born 13 May 1963.

"Would it not be better if one could really 'see' whether molecules...were just as experiments suggested?" Dorothy Hodgkin, born 12 May 1910.

"I never pay attention to anything by 'experts'." Richard Feynman, born 11 May 1918.

"Nature is not embarrassed by difficulties of analysis. She avoids complication only in means." Augustin Fresnel, born 10 May 1788.

Physics Quote of the Day (May 3 - May 9)

"Concepts like these can seem remote, until you explain with analogies taken from everyday life." Leonard Mandel, born 9 May 1927.

"...still many physicists are convinced to "see" the particle in a cloud chamber or on a scintillation screen, therefore accepting classical particle coordinates as pieces of reality. But what one concludes to see depends on the chosen model of reality..." Dieter Zeh, born 8 May 1932.

"An essential aspect of creativity is not being afraid to fail." Edwin Land, born 7 May 1909.

"... an experimentalist should not be unduely inhibited by theoretical untidyness. If he insists in having every last theoretical T crossed before he starts his research the chances are that he will never do a significant experiment." Robert Dicke, born 6 May 1916.

"Anything worth doing is worth doing twice, the first time quick and dirty and the second time the best way you can." Arthur Schawlow, born 5 May 1921.

"... numbers, even whole numbers, are words, parts of speech, and [...] mathematics is their grammar." Carl Eckart, born 4 May 1902.

"The landscape is magic, the trip is far from being over." Carlo Rovelli, born 3 May 1956.

Physics Quote of the Day (April 26 - May 2)

"Research can be undertaken in any kind of environment, as long as you have the interest. I believe that true education means fostering the ability to be interested in something." Sumio Iijima, born 2 May 1939.

"It is so difficult to find something interesting and new, but instead of helping me to develop fledgling ideas in their infancy, you guys immediately look for a way to attack them." Gersh Budker, born 1 May 1918.

"You know that I write slowly. This is chiefly because I am never satisfied until I have said as much as possible in a few words, and writing briefly takes far more time than writing at length." Carl Friedrich Gauss, born 30 April 1777.

"Time and Space... It is not nature which imposes them upon us, it is we who impose them upon nature because we find them convenient." Henri Poincaré, born 29 April 1854.

"Oh, that's nothing - I could coach a coal scuttle to be Senior Wrangler." Peter Guthrie Tait, born 28 April 1831.

"Part of the strength of science is that it has tended to attract individuals who love knowledge and the creation of it. Just as important to the integrity of science have been the unwritten rules of the game. These provide recognition and approbation for work which is imaginative and accurate, and apathy or criticism for the trivial or inaccurate... Thus, it is the communication process which is at the core of the vitality and integrity of science..." Philip Abelson, born 27 April 1913.

"If you don't want to be replaced by a machine, don't try to act like one!" Arno Penzias, born 26 April 1933.

Quantum mechanics is best understood when you're blind

Occasionally I go through some threads of newsgroup sci.physics.foundations. This moderated newsgroup is dedicated to my main subject of interest and one is bothered neither by flames or spam as in sci.physics nor with biased moderation. So for everyone with an interest in physics foundations, this is a good place to be.

Recently there have been discussions on the difference between classical and quantum. I appreciate the description given by Charles Francis, which I quote hereafter:

Classical mechanics is the mechanics of bodies whose position can be continuously known up to the limit of experimental accuracy.

Quantum mechanics is the mechanics of particles whose position cannot be known between observations even in principle.

I like the fact that this definition goes beyond the historical bias that ordinary objects behave classically and submicroscopic particles behave quantum-mechanically. Charles Francis's definition focuses on the way we describe the behavior of objects, not on the way the objects behave. In other words, this definition doesn't assume a boundary between classical vs. quantum bodies. It merely assumes that we may choose between two descriptions. It assumes we have bodies and particles and we can choose to describe them either classically or quantum-mechanically. This point is very important: it empowers us to go beyond the historical bias. We just have to set up a suitable experimental procedure where:

• positions cannot be known between observations even in principle --> use quantum mechanics.
• positions can continuously be known --> use classical mechanics.

So a body is neither classical nor quantum, it just is. Depending on our purpose, we choose to describe it classically or quantum-mechanically.

As an illustration, we may refer to the perception of blind people. A blind man relies on his blind stick to analyze the behavior of objects surrounding him. He cannot know the position of objects between two "blind stick observations" even in principle. His blind stick "scans" the objects quantum-mechanically, with intrinsic uncertainties, intrinsic probabilities. At each hit of his stick against an object, the "state" of that object collapses at the location of interaction. It had some probability to be detected at any other place depending on the environment, on the boundary conditions and on the respective angles (phases) of the stick and the geometry of the detected object, but the fact of detecting the object collapsed the body at a specific location. It instantly pops up at that location.

I guess a blind man will intuitively choose a quantum-mechanical description with states whose phase varies with time and location, with probabilities, with uncertainties, with interference patterns, etc. Teaching him to describe the world classically would be counter-intuitive because he cannot continuously know the position of the objects. He has to infer it with square state (blind stick projected on detected object) probabilities.

Paradoxically, we could say that quantum mechanics is best understood when you're blind...