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Although atoms had been discussed since antiquity as a theory of matter it was only at the beginning of the 20th century that convincing evidence was found, through brownian motion - in fact this was the same 'evidence' alluded to by Lucretious in his poem de Rerum Natura, as well the theory of elements in chemistry.

Although atoms were too small to see by even the most powerful microscope it was natural t think that they had the same kind of reality as a rock, as one could just simply imagine shrinking a rock to the dimensions of an atom.

It was then quickly discovered that atoms had been misnamed - they weren't the smallest particles of matter - these were elctrons, protons & neutrons. Of course, after the advent of QM and in particular QFT the picture changed. Instead of a particle we had a particle field. In the physical theory this is defined at every point of spacetime.

Doubt was thrown on the naive realism for the ontology of atoms had before.

An instrumentalist/operational ontology seems unsatisfying to me - as this doesn't seem like a proper ontology - is it natural to assume that the electron field is physically real. This subsumes the operational perspective, since then a measurement just measures an interaction with the field - so measurements are real.

I mean by the physical reality of the field that they have the same kind of reality as a rock. What are the problems or criticisms can be made for this view?

It appears strange for example, we can say that a field is physically real and so is a rock but their physical reality differs.

By this I'm not claiming physicalism, that everything in the world is physical. Or that only physical laws are real.

Is a fair criticism is that we have no right to expect that physicists won't decide a better model of an electron is not a field but (for want of a better word) a forest - a new mathematical gadget. Are we then committed to the reality of a forest, and no longer to the field?

  • Related essay by Dyson: clerkmaxwellfoundation.org/DysonFreemanArticle.pdf – user3164 Jun 4 '13 at 11:28
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    Wikipedia: "From the point of view of quantum field theory, particles are identical if and only if they are excitations of the same underlying quantum field. Thus, the question "why are all electrons identical?" arises from mistakenly regarding individual electrons as fundamental objects, when in fact it is only the electron field that is fundamental." [Bold mine.] – user3164 Jun 4 '13 at 11:32
  • Define "Real." But really: If you rephrase "Do electrons have electrical fields around them that have a causal effect," the answer is "Yes." – medivh Jun 24 '13 at 12:52
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Hawking gave a nice remark in one of his pop books concerning the reality of his imaginary new time dimension.

"One might think this means that imaginary numbers are just a mathematical game having nothing to do with the real world. From the viewpoint of positivist philosophy, however, one cannot determine what is real. All one can do is find which mathematical models describe the universe we live in. It turns out that a mathematical model involving imaginary time predicts not only effects we have already observed but also effects we have not been able to measure yet nevertheless believe in for other reasons. So what is real and what is imaginary? Is the distinction just in our minds?"

reference: http://en.wikipedia.org/wiki/Imaginary_time

So to your question, they as real as long as you believe they are to be so.

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    I can't say that I'm keen on positivism - its too much like turning a scientific method into a philosophy of ontology. Its true we can't determine whats real - that's beyond the ability of empirical science (as also confirmed by Feynman in his book the Character of physical law), but that is why we philosophise...or get others to do it for us. – Mozibur Ullah Jun 4 '13 at 12:20

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