Sure you can. You don't have to have a degree in English and be a writer or editor to read a book and know it's trash. Same with art. You may not understand all of the nuances or the movements it comes from...but if you have to know all of that to know if it's art or not, doesn't that defeat the purpose? Art is supposed to get its own message across without needing an explanation beforehand.

And then, it still comes down to personal preference. What I consider trash in a book or a movie may be the greatest thing someone else has seen or read. I may not agree with their opinion, but it's still valid.