Nothing in this world exists in isolation, and texts are no exception. Any piece of writing exists in context of all the other texts that were written before and will be written after. It may not have immediate connections to most of them, but it may be related to any of them. Some thinkers even support a rather postmodernist idea that all texts that ever were written and will be written are parts of one enormous, constantly growing text bloated with cross-references and allusions.
This goes double for academic writing. A piece of fiction can, theoretically, exist separately – it still will be a subject of innumerable influences, it will repeat the motives present in other texts, it will use commonly accepted tropes, either consciously or subconsciously, but these connections are usually implicit (it is far too easy to be accused of plagiarism otherwise).
Academic writing, however, can’t get away with it. It’s very nature presupposes that every piece of academic writing should be supported by the findings published in other works by other authors, that it should use methods established in accepted guidelines, that it should list all the sources of information in its bibliography. It is not optional – an academic writer that doesn’t use research done by other people isn’t treated seriously. Thus, any academic paper from the very beginning is created as a part of a much larger whole, and to a very real extent its worth is evaluated judging by how firmly it is attached to the body of existing research.
When it comes to teaching and learning academic writing, understanding intertextuality means understanding the so-called discourse communities. That is, when a student learns the peculiarities of academic writing pertaining to a particular discipline, his or her main goal is to learn the discourses of the communities he or she is willing to join. As a result, student will inevitably try to reproduce already existing texts in his or her own works – not because of lack of something to say, but because it is the only way to learn how to produce texts that will be acceptable in the discourse community. As the student’s mastery of discourse grows, he or she will, ideally, become more and more capable of following its principles while using his or her own voice – but connection with pre-existing texts isn’t going anywhere. It simply becomes more subtle – instead of incorporating parts of other people’s works he or she will build upon them.
Intertextuality can be even found in the voice of every particular student – as one tries to find one’s own voice, one will borrow from the discourses of community one tries to enter, but there are other discourses, implanted in what one brings with oneself. As a result, any writing workshop becomes an amalgamation of numerous discourses and cultures: some already accepted and normal in the said community, while others brought by the students to be incorporated in the larger whole.
As a result, intertextuality as a principle permeates the entirety of academic world – from writing per se to the styles of particular writers.