Exploring the Physics of 1900s: Believing the Unbelievable?

[MichPod]

TL;DR Summary

How exactly could physicists believe the physics was nearly completed by the end of 1800th?

It's well known that the relativistic and quantum revolution came as a surprise for many after it was generally believed that the physics is mostly complete, except for some local problems like black body radiation etc.
Less known is the fact that the atomistic theory was not commonly accepted among the physicists until the very beginning of 1900th.

I so wonder what the world could look like fundamentally for those physicists who believed that the physics is complete?

The nature of charge? Well, we do not know it either, but these scientists even did not know of the electron nor of any other charged particle or charge carrying substance.
The nature of rigid bodies? There are so many chemicals, starting with the simplest ones and ending with our own living body. Each having different physical, mechanical, optical qualities (not even to mention chemical qualities). And so part of the physicists did not recognize the mere existence of atoms and those who did recognize - obviously could not say much about how so various physical qualities are determined.

IMO, one did not need to have any existing problem or paradox in physics (like black body radiation) to recognize that the physics is majorly incomplete, not being able to explain matter structure or its qualities.

So, how could these physicists ignore all this and believe that the physics is almost complete?

Well, looks like a rather philosophical or even psychological question, but may be if we could answer it, one could also realize what may be missing in the physics right now?...

 

[Andrew Mason]

These notions (i.e. that "physicists" at the end of the 19th C believed that there was nothing in physics to be discovered) appear to come from out-of-context statements attributed to Lord Kelvin and Albert Michelson.

Albert Michelson (of the Michelson Morely experiment fame) did say in 1894 (as reported in the University of Chicago Annual Register in 1896):

"While it is never safe to affirm that the future of Physical Science has no marvels in store even more astonishing than those of the past, it seems probable that most of the grand underlying principles have been firmly established and that further advances are to be sought chiefly in the rigorous application of these principles to all the phenomena which come under our notice. It is here that the science of measurement shows its importance — where quantitative work is more to be desired than qualitative work. An eminent physicist remarked that the future truths of physical science are to be looked for in the sixth place of decimals. "

The last sentence of the above quote (he didn't say who the eminent physicist was) could well be interpreted in a way that gives it a very prescient meaning (perhaps predicting something like quantum mechanics): the future of physics will be found in looking at the very small.

In any event, you have to read the entire paper to see that he did not think that there was nothing new in physics to discover. Indeed, since he was dedicating a new laboratory, he was recognizing the need for experimental work to explore the world of atoms and molecules:

"It is only in very recent times that it has begun to dawn upon the mind of man that there is another world only one degree less complex and wonderful than the stellar universe, - the world of molecules and atoms. For the study of these almost infinitesimal systems of pigmy stars, we have no telescope nor even microscope to help us; but litle by little we are constructing a powerful logical engine which is destined one day ot bring the revolutions, rotations and oscillations of these minute orbs, as clearly to the mind's eye, as are now the motions of the worlds of the greater visible universe."

As far as Lord Kelvin is concerned, there is some suggestion that he may have been the "eminent physicist" to whom Michelson referred. No one has provided a source for that statement let alone demonstrated that it meant that there is nothing more in physics to discover. The quote that is attributed to Kelvin is possibly a misreading of his remarks in April 1900 published in "Nineteenth Century Clouds over the Dynamical Theory of Heat and Light". It is apparent that he was addressing the incompleteness of our knowledge with reference to heat and light. With respect to the first cloud (reconciling experiment with the theory of the luminiferous ether) he ends saying: "§ 11. I am afraid we must still regard Cloud No. I. as very dense.'. As to the second cloud (problems in reconciling Maxwell-Boltzmann kinetic theory and the equipartition of energy with measured specific heats of gases) Kelvin concludes by referring to that cloud as "a cloud which has obscured the brilliance of the molecular theory of heat and light during the last quarter of the nineteenth century."

In 1924, Max Planck did say ( Sci. Am, Feb 1996 p.10 ):

"When I began my physical studies [in 1874] and sought advice from my venerable teacher Philipp von Jolly...he portrayed to me physics as a highly developed, almost fully matured science...Possibly in one or another nook there would perhaps be a dust particle or a small bubble to be examined and classified, but the system as a whole stood there fairly secured, and theoretical physics approached visibly that degree of perfection which, for example, geometry has had already for centuries. "

Planck may have oversimplified what von Jolly "portrayed" and without an actual reliable quote it is probably unfair attribute much to the remark. In any event, in 1874 the problems with classical theories revealed by the Michelson-Morely experiment and by experimental disagreements with kinetic theory were not as evident.

To suggest that this was a view widely held by leading physicists at the turn of the century is not borne out by the record nor by what those physicists were able to accomplish in the first few decades of the 20th Century.

AM

 

[Delta2]

Summary:: How exactly could physicists believe the physics was nearly completed by the end of 1800th?

So, how could these physicists ignore all this and believe that the physics is almost complete?

I believe that they didn't exactly ignore it, they were hiding it below the "carpet" of the general building of classical physics. Classical physics consisting of Maxwell's equations, Navier-Stokes equations, Newtonian mechanics or Lagrangian-Hamiltonian mechanics Statistical mechanics and Thermodynamics were able to solve almost all problems in the medium/macroscopic range but was failing in some problems in the microscopic range (for example Maxwell's equations predict that electrons orbiting around nucleus should eventually loose energy due to radiation and fall into the nucleus).

I guess physicists amazed by the huge success at the medium/macroscopic range at the end of the 19th century ,were considering "minor details" the exact details of what is happening in the microscopic world and that's why they considered physics to be almost complete by then (although blackbody radiation seems to be a macroscopic problem). Of course it turns out that the exact details of the microscopic world are not minor at all and require a whole new science of quantum mechanics and quantum field theory in order to be successfully resolved.

I cannot blame the physicists at the end of the 19th century though, because now at 2020 when i look at technological miracles like computers, they can almost fully be explained by classical physics. I believe even modern computers can be explained by maxwell's equations alone, if we again disregard some "minor" details regarding the internal operation of transistors (the physics of the PNP junction for example) that require quantum physics in order to be fully explained.