Dietrich Bonhoeffer writes, in a letter to a friend, that interior music often surpasses the music of physical hearing; it is purer, and somehow acquires a ‘new body’.  Certainly, there are no ‘mistakes’, tuning faults, or other flaws in interior music, music one plays to oneself in one’s head (or, perhaps in some cases, there are), but there might not be any of these in a physical performance.  The physical performance could be technically ‘perfect’.  So how, then, is an interior performance more ‘pure’?  Is an interior performance more intimate?  More attuned to the musical needs of the only listener?  As to it having a ‘new body’, I can’t say I’ve ever experienced it in this way.  I suppose that individuals have different degrees of ability to perform ‘music in the mind’.  I do it quite often, but often only fragmentarily, and largely by accident.  I don’t play music in my head for my own entertainment.

Then again, if I had been in confinement as long as Bonhoeffer had, perhaps I would have played music in my mind deliberately.  Perhaps it is only through being given the opportunity to focus on interior music that Bonhoeffer could contemplate it and experience it fully.  Indeed, in his case, he enjoyed playing music in his mind, whereas to most people it is a mild annoyance interrupting other tasks.  I couldn’t help but think that, although being imprisoned is extremely costly in terms of freedom etc. (not to mention the fact that Bonhoeffer was then executed), Bonhoeffer had an opportunity to think, read, and write; not many people take time out to do these things.  Bonhoeffer had nothing else to do, given his confinement, and though it was a tragedy, he at least could receive books, write letters and papers, and receive letters.  He would perhaps have thought very differently had he not been imprisoned, and thus was moved towards considering these things by the music he played in his head, the birds singing nearby, and other stimuli particular to his circumstances.

Bonhoeffer thought about life in musical terms; he discussed, again in a letter to a friend, the ‘polyphony of life’.  In this way, he used musical analogies to portray his thoughts on love and Christianity.  He thought of human love as needing a cantus firmus, in the shape of divine love, and of counterpoint as representing the twofold divine and human nature of Jesus, in it being two parts without confusion, yet distinct.

Music is still often used as analogy to theological thought, or as a model.  There is nothing wrong with this, though it is only one level of relationship between music and theology.