4

I was chatgpting and found Encouragement of the Mechanistic View The mechanistic view in physics is driven by several key principles:

Determinism: The idea that the future behavior of a system can be predicted with complete accuracy if its initial conditions and the laws of motion governing it are known.

Reductionism: The belief that complex phenomena can be understood by breaking them down into their simpler constituent parts and studying these parts individually.

Causality: The principle that every effect has a specific cause and that the laws of physics govern these cause-effect relationships.

Locality: The notion that interactions between objects occur at specific points in space and time, without instantaneous action at a distance.

My question is: What encourages a mechanistic view and how its related to reductionism and determinism ?

One blow to mechanical view was I think was action at a distance but does the concept of fields kept the concept of mechanistic view by introducing the concept of locality and answer to action at a distance ? Please explain to me the intricate relationship between causality and locality .

Anyone interested must read https://dn720201.ca.archive.org/0/items/evolutionofphysi033254mbp/evolutionofphysi033254mbp.pdf

14
  • 1
    i think your question as it is lacks clarity, but that it is essentially a good question, that it can be a good question. dunno how to edit it
    – andrós
    Commented Jun 24 at 6:47
  • that's clearer to me, tho YMMV
    – andrós
    Commented Jun 24 at 6:52
  • 1
    @PerttiRuismäki explain
    – quanity
    Commented Jun 24 at 7:22
  • 1
    @andrós you missed the concept of fields
    – quanity
    Commented Jun 24 at 7:22
  • 1
    @quanity Reality is neither deterministic nor reducible. Therefore it is not mechanistic regardless of how causality or locality turn out. Commented Jun 24 at 15:21

4 Answers 4

4

An additional (perhaps minor) point: Maxwell himself spent his later years hypothesizing various mechanistic models for electromagnetic wave propagation in which space was filled with submicroscopic gear wheels and springs which transmitted movement by direct contact between machine elements, eliminating the need for fields as we conceptualize then today. This approach fell flat, for the following reasons:

To get the measured speed of light to come out correctly required that those little gear wheels and whatnot be almost massless and the springs and whatnot be almost infinitely stiff- ruling out any form of ordinary matter to make them out of.

Then you have the problem that ordinary matter can pass straight through that infinite array of space-filling gear wheels without any resistance. Hmm...

Finally you have the problem that to mechanically propagate waves in space through physical contact between gear wheels in three dimensions required those little gear wheels to mechanically engage one another in three dimensions in physically impossible ways.

3
  • Michaelson championed the Luminiferous Ether though, he really tried! The idea of a substance a million times stiffer than steel and a million times lighter than air (which matter could pass through with no resistance) filling the universe, didn't bother him.
    – Scott Rowe
    Commented Jun 24 at 19:14
  • @nielsnielsen does fields obey the mechanistic view ?
    – quanity
    Commented Jun 24 at 19:44
  • fields to not comport with Maxwellian mechanistics. modern physics has no use for mechanistics. Commented Jun 24 at 21:47
3

The term mechanistic is outdated. It characterizes Newtonian mechanics. Already in the 19th century Maxwell’s electrodynamics is a theory which cannot be understood in mechanical terms.

  1. The principle of causality holds for the physical theories of Newton, Maxwell, Boltzmann (thermodynamics and statistical mechanics) and Einstein (Special and General Theory of Relativity). The principle does not hold for quantum mechanics and quantum field theories.

  2. The principal of locality should be restricted to the first part of the definition in the OP's post. Then it holds for all of the above theories with the exception of quantum mechanics and quantum field theories: In general, the state of a quantum system has to be considered a field of probabilities (psi-function), and therefore the interaction via interference cannot be localized.

  3. The principle of separability states that physical systems which are separated in spacetime can be considered as separated systems. The principle holds for all of the above theories with exception of quantum theory: The phenomenon of entanglement in quantum theory contradicts the principle of separability.

  4. Different from the principle of locality is the principle “no instantaneous action at distance”: This principle is violated by Newton’s mechanics and afterwards Boltzmann's thermodynamics and statistical mechanics. But it is satisfied by the other physical theories above. An upper bound for the propagation of the causal effect is the speed of light.

  5. The question of reduction of theories is quite a different subject. A textbook example is Boltzmann’s and Gibbs’ reduction of thermodynamics to statistical mechanics. But the possibility of general reduction is restricted. In general, distinct sciences work with additional specific laws, which will not be reduced to the deepest layer of elementary particles.

This short overview from the history of physics shows which of the above principles were successfully incorporated into which physical theories, while other principles had to be abandoned.

12
  • entanglement does not contradict locality.theoreticalminimum.com/courses/quantum-mechanics/2012/winter/…
    – quanity
    Commented Jun 24 at 8:12
  • why no causality in QM?
    – quanity
    Commented Jun 24 at 8:12
  • 1
    I think this answer would be improved by removing the first paragraph. Mechanics refers to treating physical systems as if they are machines, not Newton's use of a word which had been commonly used for that purpose for two thousand years before Newton (as Μηχανικά) and has remained in use for that purpose ever since, including among 21st century philosophers and physicists.
    – g s
    Commented Jun 24 at 16:43
  • 1
    @JoWehler Ah, alright. Most statmech texts I've used present the fundamental assumptions of statmech independent of Newtonian mechanics and then use them to derive both classical gas statistics and Bose-Einstein/Fermi-Dirac, but it makes sense when we're talking about Boltzmann
    – Kaia
    Commented Jun 24 at 18:26
  • 1
    The idea that 'mechanistic' applies to Newtonian mechanics only seems like a complete fabrication to me. I never once heard that during my (brief) time as a physics major. And it should be obvious that quantum mechanics also uses the term 'mechanics'.
    – JimmyJames
    Commented Jun 25 at 14:57
1

As you have probably understood from the book, the mechanical view of the universe is a thing of the past. Nowadays, how things works, is described (by physics) in terms of fields.

With regards to locality in a machine-like universe, you expect a specific part not to depend on, or affect another (except nearby); after all, that's what a machine is like: parts are not dependent on other parts, except if they are explicitly connected.

In regards to causality, although this concept can be "interpreted" in many ways, one thing is for sure: you expect a cause to precede the effect.

Both these concepts are challenged by the phenomenon of quantum entanglement, where a system is exchanging information with another, violating locality, while at the same time, makes cause and effect indistinguishable.

In fact the Nobel price 2022 was about this process.

12
  • @loannispaizis the locality principle applies to quantum mechanics. Let’s be as clear as possible: It does. Quantum mechanical entanglement is often referred to misleadingly as nonlocality. But entanglement is not the same as nonlocality. Entanglement does not mean you can send signals instantaneously from one place to another. Locality is fundamental
    – quanity
    Commented Jun 24 at 16:50
  • @quanity Bell explicitly defined locality, and it is NOT "signals" but causation from outside a light speed boundary. Entanglement explicitly violates locality. Events outside a light boundary affect measurement within it. Bell showed that "local realism" is not true of QM.
    – Dcleve
    Commented Jun 24 at 17:00
  • @quanity, Einstein was disproved officially in 2022, by the Nobel price Commented Jun 24 at 17:35
  • Does quantum mechanics violate locality? Some people think so. Einstein railed against the “spooky action at a dis- tance” (spukhafte Fernwirkung) that he claimed was implied by quantum mechanics. And John Bell became almost a cult figure by proving that quantum mechanics is nonlocal. On the other hand, most theoretical physicists, particu- larly those who study quantum field theory, which is riddled with entanglement, would claim the opposite: quantum mechanics done correctly ensures locality. The problem, of course, is that the two groups mean different things by locality.
    – quanity
    Commented Jun 24 at 17:41
  • @IoannisPaizis go through Susskind quantum mechanics book chapter 6 and 7 or theoreticalminimum.com/courses/quantum-mechanics/2012/winter/…
    – quanity
    Commented Jun 24 at 17:42
0

What encourages a mechanistic view...

I've already argued in a comment that a mechanistic model attempts to answer a "how" question, e.g. how does the observed motion of the planets arise? Ptolemy attempted to answer this question, and Newton produced a simpler model. This led to the discovery of the planet Neptune.

  1. Herschel discovered Uranus by good, old fashioned, observation.
  2. Initially Newton's model didn't fit the data for Uranus terribly well, but John Adams and Urbain Le Verrier realized that the model could be made to fit if there were yet another planet out there. They independently calculated the position of their hypothetical planet, which was duly observed.

Getting back to your question: a mechanistic model may predict phenomena which may or may not be observed. Mechanistic models are encouraged by this possibility.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .