I have been mulling this, off and on, for weeks.

How is that we recall passages from complicated music — familiar orchestral works, for example? Not talking about the opening chords of Beethoven’s Fifth … rather, the key passages from lesser-known works.

Is that process akin to the way in which we can hear the voices of people who are dead, or people with whom we have not spoken in years?

And does all of this often depend on connecting words to the music, and then recalling it via that route?

Many of us are familiar with the great composers. In many cases, through cartoons, where orchestral passages accompanied the action. (Thanks, Warner Bros.; thanks Disney!)

And once a tune is being played, we can anticipate the next 15, 20, 100 bars. We don’t need the music anymore to know where it is going.

But it is much harder to make that connection when the music is not present in the moment. When we do not have an aural prompt.

Quick: Hum the most famous part of Tchaikovsky’s Sixth Symphony “Pathetique”. (Go to the 16-minute mark.)

Quite a bit harder, isn’t it?

Don’t we all find it easier to remember music written with lyrics? If you can remember a sentence fragment from a pop song, your brain can reconstruct the whole of it, probably. Words and tune.

Of late, I have also been wondering about voices we once heard regularly, but no longer do.

How many do we remember?

It is not entirely about proximity in time. I can hear the voice of my grandmother who died in 1991. But time is a factor; I can no longer remember the voice of my other grandmother, who died in 1966.

Friends, relatives, entertainers … even those we have not spoken to in years, if we concentrate inside our heads we can hear their voices. The timber. The accent. The speaking style.

Isn’t that a bit odd, though? Why should I be able to remember the voice of someone I worked with for a year five years ago? Yet I can. I assume you can, too.

The brain and music. Lots going on there.