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A classical particle is in spacetime and has a continuous motion within it. Properties such as electrical charge and mass inhere within it. This description in its qualitative essentials is no different to the ancient greek atomists.

Are there any such equivalents to discussing particles in modern theories of physics? I'm not asking for philosophical concepts from ancient greek times, any time period, any culture will do.

For example, I think there may be analogies to the idea of substance in the european discourse to that of field in modern physics, but I don't understand enough about what substance is, nor who discussed it and why to say anything firm about it. Although I have the impression it may have been Aristotle that first discussed it.

  • What's the philosophical question here (as opposed to physics)? Aristotle did argue against Democritian atomism, btw. Try this if you'd like to understand substance better: plato.stanford.edu/entries/substance – danielm Jan 14 '13 at 10:44
  • @danielm: You don't think its philosophical to think about the nature of the world out there? – Mozibur Ullah Jan 14 '13 at 16:08
  • Of course I do. That's exactly what philosophers are interested in (although not "out there" but all of it). But while philosophers are interested in all knowledge, your question seems to belonging more to physics than philosophy, but it could be your wording that's unclear. Philosophical problems occur here when physics and philosophy begin to conflict (whether certain kinds of atomism renders the world unintelligible, the problem of substance in atomistic theories, whether modern atomism is a necessary interpretation of experiment), or concerns methodology. – danielm Jan 14 '13 at 18:30
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Philosophical Physics by Vincent Edward Smith discusses (ch. 6: pp. 181 or PDF pp. 98 ff.) how elementary particles have less being than, e.g., a human; hence, they are more indeterminate.

Wolfgang Smith's Quantum Enigma (cf. his related article) discusses the relation between what he terms "corporeal bodies" (what we sense with our external senses) and "physical bodies" (what modern physics conceives, e.g., atoms).

Werner Heisenberg recognized in his Physics and Philosophy that the probability wave concept in quantum mechanics "was a quantitative version of the concept of 'potentia' in Aristotelian philosophy" (p. 41) and that the "concept of the soul for instance in the philosophy of Thomas Aquinas was more natural and less forced than the Cartesian concept of 'res cogitans,' even if we are convinced that the laws of physics and chemistry are strictly valid in living organisms." (p. 80).

This discussion of hylemorphism and modern science might help.

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What about the standard definition in modern physics (e.g. relativistic or quantum field theory), i.e. that elementary particles correspond to irreducible representations of the relevant symmetry group of transformations which leave the physics (Lagrangian) invariant? Special relativistic locality follows from causal field constraints, I think. You might try Quantum Field Theory for the Gifted Amateur, an ebook, or more philosophically the book "How is Quantum Field Theory Possible" by Auyang.

  • Well that is physics-speak; but its noticeable that the 'atomicity' of the electron roughly corresponds to irreducibility of the representation; and that the symmetry to that of the symmetry of the particle - I'm thinking here of an antique description of atoms as platonic solids. – Mozibur Ullah Nov 13 '14 at 16:37
  • Thanks for the references, I haven't come across them before - and they look useful. – Mozibur Ullah Nov 13 '14 at 16:40
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The modern concept of "particle" is that it has no properties except when "measured". The quantum fields that are used to calculate observational/experimental results cannot be thought of as "existing entities" in anything like a classical sense. (They vanish everywhere but at points of interactions so it makes no sense to think of them as something existing in space time just before the interaction which then vanishes when the "particle" or property is localized or somehow detected. We aren't really detecting "particles" but that is the terminology used out of habit. The concept of "matter" also is obsolete since any self respecting matter would never act like a quantum field. The word "substance" is , I suppose less restrictive, but one would have to have some observational account of it to see how it might fit into our theories.

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The intuitive concept of particle is alive and well in experimental particle physics (and to a lesser extent particle phenomenology) . Check out the listings in the Particle Data Group Handbook tables upon tables of numbers that describe the discrete features of the countable objects that are studied at particle colliders. The operators at LHC know (approximately in practice, exactly in principle) the number of protons that are in their beam packets. When they make event reconstructions (below) they "fill in" the particles' trajectories. The point here is that for doing some aspects of modern high energy physics, the basic notion of "particles bouncing off one another" is still there, only modified to use QM in calculating (describing) what is entailed in "bouncing off".

enter image description here (from http://lhcb-public.web.cern.ch/lhcb-public/)

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