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.
Gist of Idea
The Higgs field, unlike others, has a nozero value in a state without particles
Source
Brian R. Martin (Particle Physics [2011], 09)
Book Reference
Martin, Brian R.: 'Particle Physics' [One World 2011], p.148
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.
Related Idea
Idea 21201 A 'field' is just a region to which points can be assigned in space and time [Martin,BR]