From the opening section of a book on the many-body problem:
“It might be noted here, for the benefit of those interested in exact solutions, that there is an alternative formulation of the many-body problem, i.e., how many bodies are required before we have a problem? G. E. Brown points out that this can be answered by a look at history. In eighteenth-century Newtonian mechanics, the three body problem was considered insoluble. With the birth of general relativity around 1910 and quantum electrodynamics in 1930, the two- and one-body problems became insoluble. And within modern quantum field theory, the problem of zero bodies (vacuum) is insoluble. So, if we are out after exact solutions, no bodies at all is already too many!” (emphasis added)
In modern quantum, theoretical, and particle physics, physicists quite literally can’t solve nothing. This is not a double negative- “nothing” is already a problem with no exact solution, and anything more than nothing is even worse. Some progress.