Philip K Dick wrote a science fiction book about a universe where two giant ad agencies fought each other to rule the galaxy.
These days it would take a different type of Dick to think that's at all likely.
As ad agency groups struggle to survive by downsizing and cutting out unnecessary luxuries like creative departments, it's more likely that the galaxy would be run by a couple of corner shops or exhaust replacement services.
Except.
In Japan.
Where Dentsu is.
6,000 people go to work there every day, in a building the size of a whole block, designed by the guy who designed the Pompidou centre in Paris.
(Is there another Pompidou centre ? I think they were planning to build one in Croydon.)
I was comtemplating all this as I was standing on the 44th floor, looking out at Tokyo harbour and talking to the former President of Dentsu.
This is the VVVIP floor where they keep the pricelesss antiques like vases from the Edo period and what looked like an old Frank Lowe cricket sweater from the time when Dentsu bought CDP.
I remember Jay Chiat telling me once about a Dentsu Christmas party. He told me that one whole floor had been devoted to Japanese pornography, although I think he may have been confusing it with one of the electronic stores in the Akihabara distrtict.
He was telling me how he'd climbed Mt Fuji 15 times - this was the ex-president of Dentsu, I don't think Jay Chiat ever attempted to climb Japan's highest mountain.
But apparently everyone in Dentsu has to climb it when they join or get promotion.
Since this kind of corporate groupthink gives me the willies, I made polite noises. I was just thinking how if I'd joined Dentsu the lung-shredding experience of slogging up several thousand feet for 7 hours would have disincentivised me from seeking any kind of promotion at all, and my career could have ended (possibly quite blissfully) as a 50-year-old junior copywriter working on trade mailers.
Other highlights of the trip for me were hanging out with people like Brett Mitchell from Droga 5 in Sydney, in the searing heatwave that hit Tokyo.
And a very interesting dinner with Mori Harano of Drill Inc, the digital hotshop, who told me how he saw the future of our industry as we ate raw horsemeat in a restaurant owned by one of the country's leading kabuki actors. The horse was absolutely delicious, although Mori's view that the future of marketing wouldn't need copywriters or art directors was a little less easy to digest.
He's probably right though - it's all going to be about product design and social media and content creation and actually there's no need for advertising at all.
Then there was the dinner in an achingly cool restaurant with dishes I couldn't begin to describe hosted by David Elsworth, the Coke client for Japan. A few years ago in Cannes I realised that clients think they're the new rock stars - and sometimes you meet clients who actually are gifted and visionary. David's one of them, a man with more energy than a department store full of Japanese high school girls.
And if that's your bag, Shibuyua 109 is the place to go. It's an intense experience, not least because you're surrounded by young girls all trying to out-weird each other - because the most outrageous ones get picked out of the crowds and chosen as designers for the small boutique stores there.
And then there was the discussion with Jonny Shaw of Naked in a new-age bar in Roppongi about the social revolution happening in Japan right now.
The young guys in Tokyo are called something which translates as "herbivores" because they reject the macho capitalist views of their fathers. They're not interested in money or power or drinking whiskey with paid companions or climbing the corporate ladder and it drives the older generation mad.
Since a lot of the young guys aren't interested in girlfriends or getting married, it's freaking out a lot of young Japanese women too.
It's either a complete disaster or the most brilliant youth rebellion since punk.
Either way, it'd make a bloody good film, and Johnny and I are going to write it.
Using the nom de plume of Dick N. Dick
