The great American physicist Murray Gell-Mann recently died of old age. He was born in 1929, made most of his important contributions to particle physics a half century ago, and departed from the world in his bedroom in Santa Fe, New Mexico. He was almost 90. Though he is dead, I have a bone to pick with this famous and brilliant physicist, and those of his generation (be they dead or alive). Not long after the Second World War, particle physics experienced an explosion of information about the fundamental stuff that makes reality not impossible. When these new particles popped up in bubble chambers, which was frequently and, at the time, seemingly without end, silly names for them also popped up in the heads of researchers. As a consequence, anyone who studies or attempts to make some sense of this science walks right into a surreal zoo of words.
Gell-Mann's contribution to this confusing particle zoo is the word quark, the name he gave to the stuff inside of mesons and baryons. He took the word from some passage in a book that's unreadable, Joyce's Finnegan's Wake ("Three quarks for Muster Mark! Sure he hasn't got much of a bark. And sure any he has it's all beside the mark"). Another physicist who determined the existence of these particles at the same time as Gell-Mann, George Zweig, called them, for reasons not known to me, aces. This class of elementary particles never had a chance. It was going to be quirky one way or the other.
All of that said, there is something truly fascinating about quarks. They are separate but cannot be separated. And is this not the kind of contradiction you expect to find in the deepest parts of reality? Together but not together? Weirder yet is the force that holds two quarks together. It is not like the forces we are accustomed to. Its power increases the more one pulls a single quark from the others. Distance does not weaken it but makes it stronger. As a consequence, there is no such thing in nature as a lone quark. And so, we have a thing that's not a thing in the sense that we understand as normal.
But when you get right down to it (the it being the universe as we experience it), we find events and processes that are, again and again, counter-intuitive. We also reach, again and again, the limits of knowledge. Though many people do not want to admit this, the truth is much of particle physics was exhausted by the 1970s. Indeed, its final year of glory might have been 1974, with the discovery of a particle called the J/psi meson. What the state of current physics points to is the limits of what we can know. But we are not prepared to hit a hard and insurmountable end of things. We have been raised on the sense of human intellectual boundlessness. We have the myth of progress, as codified by the Victorians, to thank for this.
But, my fellow Americans, there are really things we cannot know, such as the first events that led to the separation of the four forces that constitute our knowable universe. The split occurred deep within the first second of this universe's emergence. In that short space of time existed temperatures we can't recreate. As the cosmologist Martin Rees put it, for us, there can only be one experiment for the birth of the universe.