Intertextuality and Interdisciplinarity are closely linked in my opinion. Intertextuality claims that all text comes from text that previously was in existence(Martinez Alforo). Interdisciplinarity is the mixture of separate subjects, thus making intertextuality interdisciplinary in that the concept of intertextuality sounds very much like the scientific concept of conservation of mass, which states that matter can neither be created nor destroyed (Antoine Lavoisier, 1789).
That being said, I believe that English is the most interdisciplinary subject. English covers material from many different subjects and is used every single day in every subject. You might read a book about science or history in English, and then you use English when you read and write for other classes. English is perhaps the most useful subject.
So why are people so confused as to why someone would choose an English major? To be honest, I’m not really an English major. I am an education major with a love of and concentration in English. When the time came to choose a concentration, English was the obvious choice for me. It covers the most bases and is the most useful, besides the fact that I absolutely love to read and write. Having English in my toolbox makes the most sense to me, as I can use it to learn about other subjects which i may have to teach. Why concentrate in science when I might need to teach history, or vice versa? English is the most logical choice for me.