So, finishing-up my thoughts after reading Fields Of Force by William Berkson…
Physicists have settled into a comfortable agreement since Einstein when it comes to views on Space, Matter, and Force.
Before Einstein, Space was thought by most people of learning and/or of philosophical bent as being made-up an an invisible Ether. This Ether could communicate forces or energies such as Light; some thought it could also give rise (in variously conjectured ways) to Matter.
Descartes thought Space was completely packed with Ether-material; this type of Ether, with no empty spaces, is called a “Plenum.” On the other hand, Newton pictured Space as something that the Ether was contained within; in the places which contained no Ether, there existed only totally empty Void.
Most science educators today would tell you that since Einstein, mainstream physicists have tossed aside the idea of the Ether in favor of empty Space. However, one could argue that the opposite has occurred, that Einstein has embraced a form of Descartes’ Plenum– for Einstein proposed that Space, itself, has properties. For example, it bends toward Matter– something especially noticeable around large objects like planets.
Physicists today have mixed opinions when it comes to “action at a distance.” Newton believed that some Forces, such as Gravity, could act instantaneously between objects even over vast distances.
However, Descartes thought that forces traveled through the Ether by a sort of domino effect, as one corpuscle of the Ether transmitted energy to its neighbor, and that corpuscle to its neighbor, and so on across the Universe.
Faraday imagined energy moving via “Lines Of Force” through the Ether, and Maxwell calculated that these Lines Of Force moved at or very near the Speed Of Light.
Einstein, who imagined Light travelling across empty Space in little packets of energy called Photons, did not need any Ether to complete his worldview– but he did agree that electromagnetic forces travel at a “c”— the Speed Of Light. The idea that forces propagate at a finite speed became the standard view of physicists.
Nevertheless, in the first half of the twentieth century, mainstream Quantum Theory re-asserted that some forces or events can occur instantaneously. Specifically, neither the electron’s Quantum Leap nor the (derisively labelled) “spooky action at a distance” of Quantum Entanglement conform to the view that action occurs with continuity and possesses duration.
Interestingly, there has been a multi-century undercurrent in Physics to get rid of this whole notion of “Force”— a position that I happen to agree with.
Descartes, with his Ether domino effect did not need any mysterious “forces” beyond the simple mechanical exchange of “pass-it-on” that occurred between Etherial or material bodies in actual contact. And both Kirchhoff and Einstein thought that the idea of “Force” should be expunged from physics.
Let us take Einstein: 1) Instead of Gravity, he believed things move toward each other due to the distortion of Space caused by their masses. 2) Also, he believed light traveled as Photons. Curiously, I have never come across Einstein’s view on Magnetism, and I would be interested to know his non-force explanation for that phenomenon.
When it comes to the nature of Matter, the modern opinion, since E=mc^2 has hit the scene, is that Matter is basically a very, very condensed form of Energy. Before Einstein, most physicists assumed that Matter and Energy were distinct phenomena. The atomic, or at least molecular view, was very common– that Matter is comprised of smaller and smaller pieces of, well, Matter. This Matter was also the source of Forces– such as Gravity, or for charged particles, electrical energy.
There were exceptions, of course– notable ones. Faraday thought that Matter was created where Lines Of Force crossed. For Faraday, Force-Fields did not emanate from Matter, Matter was created from Force-Fields.
Descartes believed that Matter was formed from extremely small disturbances in the Ether that he imagined as vortexes. Kelvin promoted a very similar view (we often call his version of the Ether-vortices, “smoke rings”).
Electricity was never much focused upon til the late 1700s. At this point, there were ideas about one or two electrical “fluids” bandied about. In the eighteen hundreds, Faraday and Maxwell thought electricity was due to Lines Of Force, but neither liked the idea that was becoming more prevalent that “charge” (whatever that is) is carried by little charged particles.
Today, the Electron is accepted as the charged particle which carries Electricity. Even Einstein seems to have accepted the standard theory of the Electron.
I, for one, do NOT. But that’s another post.