My comment was basically pointing out the irony of claiming that art history people say stuff with limited data, based on your obviously limited experience of art history as a field.
> I assume that you basically have to read up some facts and then can go to any lecture you fancy and start contributing in a more or less meaningful way.
This isn't true, unless you're an undergrad at a really bad university. The really 'unproductive' fields like art history tend to have a pretty asymptotic difficulty curve, since funding is almost impossible to find. That makes later stages really, incredibly competitive, unless you're basically willing to pay through the entire process.
One thing to note about hierarchy of perceived difficulty of university courses, is that it almost always maps to how useful these courses are to industry, and almost never maps to how complex the subject actually is. Traditional Chinese literature, for instance, is horribly difficult. Computer science, on the other hand, is a subject where people actually try hard to be understood, and don't write using in bird-worm seal script. Nonetheless, if you are a computer scientist, people will assume you're smart, and if you're studying chinese literature, people will assume you're a goof.