This is the text of the morning's Pause for Thought on the Chris Evans Show on BBC Radio 2:

I think I'm probably not alone in having from time to time a song going round my head that I can't shake off. Not that I want to, particularly, but it can sometimes be a distraction when you're supposed to be concentrating on something else and the song keeps interrupting.

The one that's buzzing through my consciousness this week sounds a bit twee, but it isn't really. It's a Bruce Cockburn song called 'Don't forget about delight'. Basically, it recognises that the world we live in is complicated, that the news crowding in on us from all sides is usually bad, that the world can often look a bit bleak. But, says the poet, don't forget about delight.

It seems to me that this is a necessary reminder, a timely prompt. To use a different metaphor, the darkest night can be illuminated by the faintest light. Or, as someone else put it, don't just curse the darkness – light a flame.

I picked up a book recently called Hope without Optimism. It's written by Terry Eagleton and makes an important distinction. Optimism is, in one sense, wishful thinking – a belief that things will get better. Hope goes deeper and is more realistic. Hope doesn't depend on a set of circumstances working out, but keeps us constant whatever the circumstances life throws at us. That's why Christian hope is rooted in the character and person of God, not in a formula for a successful life.

So, I go along with both Bruce Cockburn and Terry Eagleton – the poet and the professor. When the darkness crowds in I need to remember not to forget about delight. When the news is dominated by fear and cruelty, I must spot where love and light burn through and refuse to be extinguished. When horizons begin to narrow, I can open my eyes to the rich possibilities that lie ahead – even if hidden at the moment.

So, hopeful rather than optimistic. And, whatever else happens, never forgetting about delight. And I am quite happy for such a song to haunt my memory and imagination, making me restless for the light.