Unless I am stockpiling Great Works for a CV, then every writer is a treatise to get me through the tree I am working on
Okay--I'm stupid.
What is this "political treastise" thing? Is it an option and how do you use it?
I always just automatically make a work of art.
Of course, I only play on Prince.
Unless your first great writer is very late, 8 turns of your past culture from the turn you got your first GW is a pittance. (It would be similar to AI Babylon immediately bulbing their free Great Scientist)
It's the Writer's special ability, it uses up the Writer to generate a large sum of culture. A fixed amount, one time only. Alternatively you can use him to start a Golden Age (and use him up that way) or use him to create a Great Work to place in a slot and generate Tourism.
To answer the question, it's pretty simple -- I make Great Works when I'm going for a cultural victory, and I use him (strategically) to do a treatise when I'm not (for which you can get a policy out of easily, if you're doing it right).
My logic is simple - if I'm not going to win a culture victory, Tourism is largely irrelevant. Whereas if I'm not going to win a culture victory, I need to defend AGAINST a culture victory, so making more culture for myself helps me out there. Of course I always try to wait until winning the World's Fair, and Golden age and all that jazz if possible, but I don't see any reason to sweat a great work of writing if I'm on a warmongering or science path.
Ok, this will work much better than instantly bulbing very early writers. But I'm curious what your culture per turn output is while hosting the Worlds Fair if you didn't make any great works given that great works area also a major form a culture.
The other comment is that tourism isn't quite non-realevent for defense. If a rival is currently Exotic over you while you are unknown to them it's much easier to cancel this by you becoming Exotic over them, which only takes 10%, than to drop them to unknown.