In 1993, two Nobel prizewinning physicists, Steven Weinberg and Leon Lederman, each published books suggesting that a 54-mile-long particle accelerator, the Superconducting Super Collider (SSC), should be constructed near Waxahatchie, Texas, in order to discover the elusive Higgs scalar boson, which Lederman had semi-facetiously dubbed "the God particle." (The books were Dreams of a Final Theory, and The God Particle, respectively.) In a tour de force of bad timing, both books came out just as the United States Congress was in the process of terminating funding for the project once and for all.
Which was just as well: As it happened, the Higgs boson was discovered in 2012 by scientists working at a much smaller accelerator, the 17-mile-long Large Hadron Collider (LHC) at CERN, near Geneva.
As often happens in science, a new discovery simultaneously raises several new questions, which of course was also the case with the Higgs. For instance, Why did the Higgs particle have precisely the mass it had? Were there yet even more basic particles that lay beneath, and explained, certain attributes of the Higgs? Was there in fact more than one Higgs boson? In fundamental particle theory, unfortunately, the answers to such questions have become increasingly, and even prohibitively, expensive. Before it was cancelled, cost estimates for the SSC rose from an initial $3.9 billion to a final $11-billion-plus in 1991.
But how much is it really worth to know the answers to further questions regarding the Higgs particle? How much, if anything, would you pay to know those answers, assuming, optimistically, that you could even understand the questions, such as: How does the Higgs boson explain (if at all) the phenomenon of electroweak symmetry breaking? Science has long since reached the point where some types of new knowledge can be discovered only by building structures so absurdly cosmic, and even comic, in size as to have equally cosmic price tags. In light of this, it makes sense to ask whether the knowledge supposedly to be provided by these dollar-bill-destroying behemoths is in fact worth acquiring.
Apparently unfazed by Congressional rejection of the 54-mile-long, super-expensive Super Collider, a 2001 study group at Fermilab (whose accelerator was a relatively puny 4 miles around) seriously entertained the prospect of building a Very Large Hadron Collider (VLHC), a stupendous monster that would be fully 233 kilometers (145 miles) in circumference. This leviathan object would enclose an area that was larger than the state of Rhode Island by more than 400 square miles.
Then, in the summer of 2013, a year after the Higgs had been discovered at CERN, a group of particle physicists met at Minneapolis to propose a new, 62-mile-long collider that, they said, would allow "the study of indirect effects of new physics on the W and Z bosons, the top quark, and other systems." These proposals just keep coming, like spam, junk mail, or crabgrass. But sooner or later, enough has got to be enough, even in science, which, after all, is not sacrosanct. It's just silly to keep paying—forever, eternally, and in perpetuity—more and more money for less and less knowledge about hypothetical specks of matter that go so far beyond the infinitesimal as to border on sheer nothingness.
Fundamental particle physicists, evidently, have never heard of "limits to growth," or limits of any other kind. But they should certainly acquaint themselves with that concept, for the fundamental does not automatically trump the practical. Every dollar spent on a shiny new mega-collider is a dollar that can't be spent on other things, such as hospitals, vaccine development, epidemic prevention, disaster relief, and so on. Particle accelerators the size of small nations are arguably well over the financial horizon of what's reasonable to sacrifice for a given incremental advance in arcane, theoretical, almost cabalistic knowledge.
In a postmortem on the Superconducting Super Collider ("Good-bye to the SSC"), Daniel Kevles, a Caltech science historian, said that basic research in physics should be pursued, "But not at any price." I agree. Some scientific knowledge is simply not worth its cost.