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27. Natural Reality / B. Modern Physics / 2. Electrodynamics / b. Fields

[foundational background containing particles]

14 ideas
Faraday's single field of variable forces introduces a criterion of Unity into what is ultimate [Faraday, by Harré/Madden]
     Full Idea: In Faraday lines of force picture the directional structure of powers,...so the fundamental entity is a single, unified field. ...A new criterion of the ultimate has stepped in: Unity. The universal field is still the final explanation, but not invariant.
     From: report of Michael Faraday (Experimental Researches in Electricity [1859]) by Harré,R./Madden,E.H. - Causal Powers 9.II.B
     A reaction: Almost Parmenides, except that the field is not invariant. But that was always the ancient objection to the One - that it offered no explanation of change.
Maxwell introduced real fields, which transferred forces from point to point [Heisenberg]
     Full Idea: In the theory of fields of force one came back to the older idea, that action is transferred from one point to a neighbouring point. ...With Maxwell the fields of force seemed to have acquired the same degree of reality as the body's of Newton's theory.
     From: Werner Heisenberg (Physics and Philosophy [1958], 06)
The concept of a field gradually replaced the substances in explaining relations between charges [Einstein/Infeld]
     Full Idea: In the beginning the field concept was no more than a means of facilitating the understanding of phenomena. ...In the new field language it is the field and not the charges themselves which is essential. The substance was overshadowed by the field.
     From: Einstein,A/Infeld,L (The Evolution of Physics [1938], p.151), quoted by Penelope Maddy - Naturalism in Mathematics II.4
     A reaction: This is very important for philosophical metaphysicians, especially those like me who want to explain the universe by the nature of the stuff that composes it. The 'stuff' had better not be simplistic individual 'substances'.
Quantum fields contain continual rapid creation and disappearance [Close]
     Full Idea: Quantum field theory implies that the vacuum of space is filled with particles and antiparticles which bubble in and out of existence on faster and faster timescales over shorter and shorter distances.
     From: Frank Close (Theories of Everything [2017], 6 'Intro')
     A reaction: Ponder this sentence until you head aches. Existence, but not as we know it, Jim. Close says calculations in QED about the electron confirm this.
Energy fields are discontinuous at the very small [Molnar]
     Full Idea: We know that all energy fields are discontinuous below the distance measured by Planck's constant h. The physical world ultimately consists of discrete objects.
     From: George Molnar (Powers [1998], 2.2)
     A reaction: This is where quantum theory clashes with relativity, since the latter holds space to be a continuum. I'm not sure about Molnar's use of the word 'objects' here.
In theories of fields, space-time points or regions are causal agents [Field,H]
     Full Idea: According to theories that take the notion of a field seriously, space-time points or regions are fully-fledge causal agents.
     From: Hartry Field (Science without Numbers [1980], n 23)
A 'field' is just a region to which points can be assigned in space and time [Martin,BR]
     Full Idea: The word 'field' is simply a shorthand way of saying that a physical property is assigned to the points of space and time in a region.
     From: Brian R. Martin (Particle Physics [2011], 01)
     A reaction: This is disappointing because I had begun to think that fields were foundational for modern ontology. Turns out they are operational abstractions (according to Martin). Note that a field extends over time.
The Higgs field, unlike others, has a nozero value in a state without particles [Martin,BR]
     Full Idea: The Higgs field has the property of having a nonzero value in a state without particles, the vacuum state. Other fields are assumed to have a value zero in a vacuum state.
     From: Brian R. Martin (Particle Physics [2011], 09)
     A reaction: This seems to make a big difference to our concept of a field, since it has a measurable reality even when there are no particles. So it isn't just a geometrical frame for locating particles.
A 'field' is a property with a magnitude, distributed across all of space and time [Baggott]
     Full Idea: A 'field' is defined in terms of the magnitude of some physical property distributed over every point in time and space.
     From: Jim Baggott (Farewell to Reality: fairytale physics [2013], 2 'Quantum')
     A reaction: If it involves a 'property', normal usage entails that there is some entity which possesses the property. So what's the entity? Eh? Eh? You don't know! Disappointed...
Fields can be 'scalar', or 'vector', or 'tensor', or 'spinor' [Baggott]
     Full Idea: Fields can be 'scalar', with no particular direction (pointing, but not pushing or pulling); or 'vector', with a direction (like magnetism, or Newtonian gravity); or 'tensor' (needing further parameters); or 'spinor' (depending on spin orientation).
     From: Jim Baggott (Farewell to Reality: fairytale physics [2013], 2 'Quantum')
     A reaction: [compressed] So the question is, why do they differ? What is it in the nature of each field the result in a distinctive directional feature?
In the standard model all the fundamental force fields merge at extremely high energies [New Sci.]
     Full Idea: The standard model says that the fields of all fundamental forces should merge at extremely high energies, meaning there is also a unified, high-energy field out there.
     From: New Scientist writers (Why the Universe Exists [2017], 03)
     A reaction: Not quite sure what 'out there' means. This idea is linked to the quest for dark energy. Is this unified phenomenon only found near the Big Bang?
There are about fifteen particles fields, plus a few force fields [Rovelli]
     Full Idea: There are about fifteen fields, whose quanta are elementary particles (electrons, quarks, muons, neutrinos, Higgs, and little else), plus a few fields similar to the electromagnetic one, which describe forces at a nuclear scale, with quanta like photons.
     From: Carlo Rovelli (Reality is Not What it Seems [2014], 04)
     A reaction: According to Rovelli, this sentence describes the essence of physical reality.
The world consists of quantum fields, with elementary events happening in spacetime [Rovelli]
     Full Idea: The world is not made up of fields and particles, but of a single type of entity: the quantum field. There are no longer particles which move in space with the passage of time, but quantum fields whose elementary events happen in spacetime.
     From: Carlo Rovelli (Reality is Not What it Seems [2014], 04)
     A reaction: If you are not a scientist, there is (I find) a strong tendency to read and digest stuff like this, and then forget it the next day, because it so far from our experience. Folk like me have to develop two parallel views of the nature of reality.
Because it is quantised, a field behaves like a set of packets of energy [Rovelli]
     Full Idea: Since the energy of the electromagnetic field can take on only certain values, the field behaves like a set of packets of energy.
     From: Carlo Rovelli (Reality is Not What it Seems [2014], 04)