The thought that I'm reading something written 150 years ago fills me with a keen sense of wonder.

I've begun re-reading Sherlock Holmes. The writing style of the Sherlockian canon is admittedly archaic, yet the ideas raised there feel no more dated than those in modern texts.

Arthur Conan Doyle really did produce a lasting hit. Sherlock Holmes still lives on in popular memory. The canon has completely outlived him.

In Jungian terms, 'Sherlock Holmes' is almost mythic now - he's an idea-form, not merely a fictional man.

Holmes is no longer just 'read' - he is inherited. Consider:

• Shows, adaptations and derivatives continue to be made - with no need to explain who Holmes is.

• The idea of Holmes and Watson so resonates with people, that they are often reimagined beyond the robes of Victorian-era gentlemen: as steampunk adventurers, monster-hunting Lovecraftian occult investigators, sci-fi spacenauts, and so on.

• Having lasted at least a hundred years, Holmes will likely remain popular for a hundred more. (I have every confidence that, however humanity evolves even in the age of AI, Holmes and Watson will one day be remodelled as cyberpunk neural netrunners.)

Which makes me realise: people often think of children as their legacy.

But if one were concerned with lasting legacies, perhaps it might be a more meaningful endeavour to leave behind intellectual legacies - writ in ink, or cast in bytes. (Or best, cut in stone.)

For great ideas far outlast the human vessels that carry them.