The Jhanas are a framework, not a reality.

In some lines of Buddhism, the jhanas are emotional events that a practicing meditator may experience along the way toward enlightenment. The usual description of them is in stages or, as we might say today, leveling up: you experience "The first jhana," and then the second, and so forth, until you attain the fourth, which most meditators agree is both the most interesting and the most dangerous— people can get "stuck" in the fourth and become highly delusional, convinced that they've attained mastery of themselves and maybe have found all manner of psychic powers or whatnot.

I'm suspicious of this description, because I'm suspicious of Maria Montessori and Elizabeth Kubler-Ross. Montessori taught that children go through three distinct and concrete stages, and while there's some overlap these stages more or less coincide to seven years of a child's life: 0 to 7, 7 to 14, 14 to 21, each of which is characterized by a set of concrete traits that a child is developing, and the choice of which traits gets trained and emphasized is the responsibility of the parents and teachers. Kubler-Ross taught the five stages of grief, and claimed that the dying patient went through them in a fairly linear fashion. (It was only afterward that we started applying the stages of grief to the survivors, and then to anyone experiencing the aftershock of some disaster other than the death of a loved one.)

Kubler-Ross's prescription is nonsense unsupported by the evidence. Montessori's stages of development have likewise not been vetted for any correspondence to reality other than anecdote, which puts both of them in the same category as the jhanas.

What the jhanas, Montessori and Kubler-Ross all have in common is a framework onto which those teaching and those experiencing the teaching can channel their energies into handling one thing at a time. Enough people can be convinced that Kubler-Ross's framework is "true" that they can channel their emotional energy into handling that one particular experience, be in anger or denial or bargaining. Enough children succeed and even thrive under Montessori's program (mostly, I suspect, due to the intensely attentive nature of the adults conducting the program) that parents can be convinced it's "true" and works for all children. And the jhanas are likewise useful enough that when the student experiences something like one the teacher can say, "Ah, that's close to a first-level jhana, here's what you can expect," and the student will search for those experiences and filter out everything else until the teacher says, "Now here's what you should look out for the second jhana..." and, even if the student has been experiencing those phenomena for some time, now that experience gets attention and the student starts to level up.