According to the [SEP](http://plato.stanford.edu/entries/quantum-field-theory/#Wigner):

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> Wigners pioneering identification of the types of particles with irreducible unitary representations of the Poincare group has been exemplary until the present.
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> Regarding the question of whether Wigner had supplied a definition of particles, one must say that though he has contributed a valuable and fruitful *classification* of particles; his answer does not contribute very much to what a particle is and whether a given theory can be interpreted in terms of it.
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Classically we think of an electron as a point particle which generates an electric field; one speaks of an *electron* and it's *field* - as though they are two ontologically different concepts; in a sense they are as one lacks all extension and the other does not.

The electron as a particle is generally regarded as prior, as is captured by how one speaks or writes of it.

But, in no instance do we see the bare electron without this field; so by what reasoning should we think of it as prior; other than the bias we have for atomic theories?

Let us try a little Gedanken experiment and eliminate the electron whilst leaving the field as it is.

Can we locate the classical position of the electron? Yes - by locating the position of the field with the most electric intensity.

Can we quantify the charge that this hypothetical particle has? Yes - because the relation to a field to its charge is deterministic.

Given that the particle can be determined - it's position and properties, from the field; and classically we can determine the field from the particle - so the two pictures are equivalent; then by what principle should we choose the particle picture over the field?