What is the difference between text and discourse?

While there are instances where and individuals who use
text and discourse as basically synonymous terms, there is a difference in their
definitions as regards agents (who and whom) and purpose fulfilled. In text, agents are
not a critical factor: there may agents, there may not be. For example, in CERN press
release text, there are none: information is being reported, that's all. In a novel's
text, there are agents, such as Elizabeth and Darcy in Pride and
Prejudice, who carry on a conversational discourse amongst themselves that
the reader observes. The propose of text, therefore, is to relay or communicate
information and may often be
non-interactive, meaning the reader of
the text is an observer.

While
discourse is used in a nontechnical
sense to mean conversational communication, linguistics, narratology and literary theory
have developed a technical meaning to
discourse. It is this meaning that
confuses the issue of the difference between text and discourse. To start with,
conversational discourse as between you and your friend or Elizabeth and Darcy is a
behavioral event, called a recognizable speech event, that has individual purpose.
Contrastingly, discourse in linguistics, narratology, and literary theory is a social
event of multi-layered communication in a variety of media (verbal, textual, visual,
audial) that has an interactive social
purpose.

To study text, you study the written words that communicate
some information: structure, theme, meaning, rhetorical devices, etc. To study
discourse, you study who is communicating with whom through what medium and for what
social purpose. Let’s use this answer as an example. To study or analyze the
text, you will note the overall structure and (most
importantly!) you will grasp the meaning of the content as it answers your question. To
study or analyze the discourse, you will determine who is
communicating with whom through what medium and for what social
purpose.

Let's analyze discourse together. In this answer I am
communicating with you through a textual medium--but not you alone. I am also
communicating with the larger social group made up of anyone who reads this after you
do--and the discourse goes two ways as you or others comment upon, makes notes about,
talk about, etc. my side of the discourse. This answer builds an intricate social
network of participants in a multiple-direction interactive  discourse. What is the
purpose of this discourse? Well, that is more complex; there may be many levels of
purpose.

Of the many, the most obvious purpose is to answer your
question and differentiate between text and discourse. Another purpose is for me to
articulate ideas about concepts that are important to me. Another purpose is to respect
your--and other readers--personal background and educational system while I do so. This
is discourse: it has multiple interactive layers and it has multiple complex social
purpose.

The same analysis can be applied to your conversation with
your friend and to the text of Pride and Prejudice: you can find
the multiple layers in various media that comprise the social event and the various
purposes of discourse. In summary:
Text is a behavioral non-interactive event restricted to your experience with
understanding its characteristics and its meaning or information as its singular
purpose. Discourse, in any medium, is a social interactive event with many layers of
communication and many layers of purpose.