MIDI (the musical instrument digital interface) is a technological specification; it is a series of bytes and designations of what they mean. it is a hardware and software specification, a design of a traditional metal cable that is less and less used today.

it is a design of product – a MIDI piano is different than an acoustic one.

it is a method of making music, of manipulating lighting, and of countless other artistic tasks, which prioritizes some considerations and de-prioritizes others.

for some, like music producer shawn "wasabi" serrano, it is a lifestyle.

but before it is any of these things, i posit that MIDI is an idea of an approximation.

MIDI is not first the electricity in the piano, nor is it first the cable, or the musical methods built around it, or the bytes, or the rockstar lifestyle that musicians like serrano have made out of it. rather, MIDI, at its core, is this:

you press the button, and the button does not itself make the musical sound.
nor does it send a wave representation of that sound to something else.
rather, it sends a vague approximation, with likely no more than two or three important details about the sound, to another device.
that second device interprets it, finally making the sound.

this, at its core, is MIDI;
the rest, to de-contextualize the words of rabbi hillel,
is commentary.

a similar exercise can be done for the radio.

radio is a cultural phenomenon;
it is a sector of law;
it is a profession,
a series of technological specifications,
a cliché lyrical topic in multiple eras of popular music (including, but not limited to, the eras when music was most disseminated through the radio itself).

but before it is any of those things, radio too is an idea:

you want to convey a sound, but you do not make the sound.
you do not do as you would with MIDI and convey an approximation of it.
you do not, as with cabled audio, send a metallic transcription of the same wave.
instead, you use a small section, of a limited spectrum, to reproduce a close representation of the soundwave, using various attributes of a different soundwave to encode each piece of the audio signal.
another device, some distance away, perceives the signal and turns it back into an audio wave.

so again, we can de-contextualize rabbi hillel.