What follows is a somewhat dry account, but it is the best I can offer as an explanation of what criticism does; more specifically, it might be thought of as my understanding of “formalist” literary criticism. I wrote it with a younger audience in mind, and so the second-person is brandished throughout.
T.S. Eliot reminds his readers that analysis and comparison are the chief tools of a critic.
Analysis because it allows us to identify the elements of a work (the facts about its form)
Comparison because it allows us to identify which elements are relevant and to imagine what other elements might have been in their place, or what other arrangement of elements might have been possible.
When you are asked to “notice” something about a work of literature, you are being asked to notice a choice that an author made. If you are uncomfortable with talking about an author, you are being asked to notice a feature of a work that might have been otherwise.
When you are asked to make something of what you notice, you are being asked to explain how that choice or feature of the work responds to a challenge inherent in the work’s subject matter.
Some call this sort of criticism “formalist,” but there is no reason that it cannot be “historicist” when we realize that the subject matter of a work might be understood only by way of appreciating a context that exceeds what is represented by the work itself, and when we realize that a range and significance of choices available to an author cannot be assessed except in relation to the world of language and learning of which it is a part.
But the aim of criticism–the contribution that critics make, that historians do not usually care about making–is the understanding of how the choices of a work intelligently, humanely, sensitively meet the demands of a given subject matter.
Such an understanding is two-fold, involving both a recognition of the demands inherent in the subject, as well as a recognition of an intelligent response; both are possible through engagement with the language and design of a work.
There is no saying beforehand what exactly will constitute the intelligence of a given work and there is no saying exactly which difficulties a subject matter might entail, though we might have some general notions and principles ready, gained from experience.
You might hear talk about the “form” of a work as opposed to its “content”: even if it is possible to think about one without considering the other, it is not fruitful to do so. The “form” of a work refers to the pattern and arrangement of features or elements in a work that can be thought of in terms of design, which entails a set of challenges and constraints. The subject matter of a work is its “content,” and is most fruitfully considered in terms of the challenges and constraints it presents. When the challenges and constraints are not represented in the work itself, they are referred to as its “context.” “Context” is not just anything happening around a work; it is something happening around a work that has bearing on what shape it takes.
Literary critics are, in a respect, a specialized form of historian: they investigate the history and proliferation of one sort of intelligent human behavior–the production of literature. They are interested in context when it bears on how we can understand and appreciate a work’s intelligent engagement with the challenges of its subject matter; that might result in a novel understanding of a subject matter or it might result in a new understanding of the choices available to an author.
Each time you sit to read, a tree of possibilities is before you: the genre of the book, its organization, its being in prose, its chapter titles, or lack thereof, its characters, its perspective, its first word…these are all choices that might have been otherwise. In the greatest works of literature, we feel the strength and pressure of each choice, and we realize the density and durability of the subject matter it encounters; we recognize also that its subject matter is that of life itself.
A true response to literature is a true response to life, as understood and imagined by someone else.