It’s discrete categorisation.
There have been several articles recently about the lamentable state of science in the universities. The government is planning to give £75 million to the universities for science teaching. Just where’s the money coming from? Arts Faculty budgets? Wouldn’t surprise me.
When I was doing my PhD, a flatmate of mine was also doing his, but in biochemistry. I had a major studentship from the British Academy which was worth about £5,800 p.a. He was on about £12K p.a. Science is like the privileged son, while Arts subjects are like the daughter who is merely a nuisance to be married off.
Even if science at university level is taking a bit of a hammering, it’s not as if Arts Faculties are in the ascendant. Although the perception may be that science is practical and may lead to commercial applications (i.e., profits), there’s plenty of science which is just as impractical in the so-called real world as the research output of any department in an Arts Faculty.