It is delightful in itself when we are able to interpret features of the present as signs confirming our understanding of the past. - Frank Wilczek

Particles that, like ⁴He, show constructive interference are said to be bosons—a shorthand term for "particles obeying Bose–Einstein statistics." …One way to recognize bosons is their tendency to imitate one each other. ...the presence of one boson increases the chance that another of its identical siblings will also appear in the same spot. There's an attraction between them. We will speak ...of an attractive identity force drawing together identical bosons. Lasers are a spectacular example...

If the “universe” contains everything that exists, what can be outside it? If the answer is “Things that don’t exist”, then “multiverse” becomes an idea in the domain of psychology, not physics.

In the table—and in nature—we find (leaving aside the antineutrino) fifteen fundamental fermions, with diverse strong, weak, and electromagnetic charges. ...They are so closely related by symmetry transformations that they are, so to speak, no more than different faces of the same cube.