What Is a Force of Nature?

<![CDATA[When, as a child of three, I stuck a bobby pin into a light socket and had to wear a cast for several months, I came to the conclusion that electricity exists, but I still cannot define it. I know what a “force” can do, but I do not know what a “force” is. Bosons are energy particles (photon, gluon, W, Z, graviton, and Higgs) that carry and transmit force to fermions, or matter particles, but what they are delivering, this thing we call “force,” remains inscrutable. The forces in the Standard Model that shape the world around us are due to gauge symmetries that transform the properties and actions of quarks and leptons, the building blocks of the universe, relative to one another — yet the force remains undefined, a spectral presence/non-presence.]]>