Ach, I was a bit grumpy there. In fact, I've spent the best years of my life being surprised yet again by what the Sage does know and can do. For example, a few years ago, he built me some cupboards in the bathroom. This had the added advantage of covering over a perfectly horrible brick fireplace his parents had, some 5 decades earlier, had done. I said I'd go and buy some wooden doorknobs for them. He went out. A few minutes later, he returned. He had toddled down to the churchyard, pruned a yew and turned four knobs from the pruned branch. I had no idea he could turn wood - he has a lathe, but that's for metalwork, as he did an engineering apprenticeship before learning the auctioneering business in London.
On the other hand, I don't think I'd venture to ask him if he knew who wrote, for example, Oliver Twist, just in case he doesn't. It's perfectly possible. He certainly hasn't read it. And he knows nothing at all about music. He'll come with me to a concert to be friendly and he may even enjoy it, but he won't know whether he's listening to Mozart or Chopin.
Sometimes, I wonder how we ever ended up together, because it's not for our shared interests. That is, I share his interests - a fair few of them anyway - but he doesn't share a single one of mine. It must just be his personality that attracts me.
Mind you, I still think he could have had an inkling of what an ATM is for. After all, they are normally referred to as 'cashpoints'.