Was it Sherlock Holmes who talked about the mind being like an attic? A little empty room that you had to figure out how to stock? He said the brain was like a lumber room, and you had to choose your lumber wisely, lest you end up with a head full of dross.
That's the same Sherlock Holmes who can now be seen texting on TV. For shame. Watching Holmes text is like watching Mr Darcy jive - embarrassing for both parties and requiring the same suspension of disbelief.
The Victorians, though, were partial to that sort of house analogy, comparing the brain to a broom closet, and so forth, and despite the best efforts of idiot screenwriters to update him, Holmes remains the quintessential Victorian par excellence.
It's a solid enough metaphor to use to illustrate the need to choose one's mental furniture with care.
Lumber rooms having gone out of fashion, though, the good detective might instead have to liken the contemporary mind to a modular storage unit - one of the self-assembling ones you get from Ikea, all clean lines and Scandinavian sleekness. Hopefully one that stays together and doesn't fall apart.
The storage space isn't really important, though, is what Holmes is saying, it's what you put in it that counts.
This, alas, is where I fall down. I've shown no discernment in my knowledge collection.
There's nothing on my shelves but flotsam and tat. This is because my mental lumber room has been filled with the entire contents of Trade Me and the Daily Mail.
All I have is stuff, and gossip. There's no mad woman in my brain-attic, there's only Cheryl Cole.
I'm sick of the way I use the internet. I'm sick of constantly searching the same websites for the same drivel, over and over again.
I'm sick of being a spectator in other women's humiliation at the hands of the moronic football players they married, or at the hands of other women because they don't like the way they look.
I'm sick of knowing who Shia La Boeuf is sleeping with, or what sweatshop garment Kate Middleton is showcasing when she meets a head of state.
I'm sick of looking at other people's stuff. Sick of knowing that the cumulative effect of a couple of hundred bad photos of a couple of hundred pairs of Karen Walker pants laid out on a couple of hundred white bedspreads, is a queasy sense of voyeuristic unease.
The amount of material that exists online is unimaginable; I read somewhere that the internet is running out of room.
And with these galaxies of virtual worlds to choose from, the equivalent of the great Library of Alexandria online, what do I do? I check my auctions and I update the Daily Mail. I'm not sure when this happened.
I'm not sure when I stopped using the internet to discover new things, and started using it to do the same things over and over again.
I'm online for work, of course - it's part of my job to check a wide range of websites every single day. And I still do that - I'm still roving over at least a score of the good news and current affairs sites first thing.
But what I'm noticing now is how frequently I come back to that one screeching English one, the Voldemort of tabloids, themail-who-must-not-be-named. I let my attention wander for a moment, and there I am, in front of a sidebar full of bikini bottoms and headlines trumpeting the moral panic du jour.
Obsessive at the best of times, I've developed a compulsive need to come back over and over again to this gossipy fount ... when I'm not checking out strangers' stuff on Trade Me, that is.
I'm not sure there's a lesson in this, really, except that maybe I'm drawn to the banal. There's nothing I can do about it either, except apply some unsexy principles of responsibility and self-care.
I don't need to fill my head up with junk, that's a responsibility that applies as much to websites as it does to TV.
If I don't make at least a cursory effort to broaden my horizons, I'll end up knowing nothing except where to find cut-price Kate Sylvester and what Kirsten Dunst wore this year at Cannes.
And on my head be it, as Holmes would no doubt say. The internet is a world in the ether, and like any other world it's as vast or as tiny as one's mental parameters allow.
That's why Holmes was selective about his mental furniture. I can only hope the 21st century version is keeping the faith.
I can't see what he's looking at on that blasted Blackberry, but I pray it's not the changing fortunes of a former X-Factor presenter who used to be in Girls Aloud.