I find it irksome for people to define something only on the basis of what it’s not. Sound confusing? Let me explain.

I remember way back in fourth or fifth grade at Immaculate Conception School when Sister Mary Espantosa ran us through the reading curriculum by telling us that books were generally divided into two classes: fiction and non-fiction.

Well, literature in the form of short stories, usually in prose and consisting of “made-up” stuff, constitutes a mammoth genre. And what is the counterpart of fiction? Well, it’s non-fiction. How many geniuses sat around a table coming up with a label that covers just about everything else?

There’s biography, historic literature, drama, poetry and much more to the literary canon. And all we can come up with is non-fiction? How far can we carry that game in which we categorize things on the basis of what they are not?

Let’s say we’re at a party discussing things we’ve been reading. Someone says, “I just loved the roles of Daisy Buchanan and Nick Carraway in “The Great Gatsby.” Any literate person easily recognizes the work by F. Scott Fitzgerald as fiction: it’s something the fellow made up, about some fast-living fun-loving big-spending New Yorkers in the early 1900s.

The discussion at the cocktail party likely spurs even more comment about what others have been reading. It’s true that many fictional pieces are based on facts; it’s possible that the novel J.D. Salinger wrote, “Catcher in the Rye,” is based on actual experiences in the author’s youth. We can probably say that about much fiction.

But then there are people who reason that, “If it’s not true, it’s a waste of time to read it.” In Santa Fe only recently, I became involved in a lengthy conversation about reading, the new common core curriculum and the difference between fiction and it’s unfortunately titled counterpart, non-fiction. It happened in — of all places — the blood bank, as we waited in vein.

My fellow donor, I would guess a retired teacher, like me, was insistent that too much time on the educational clock is devoted to reading “made-up stuff that anyone can write.” I begged to differ. But as I tried to make my points it became increasingly difficult to convince him that there’s much merit to stuff that’s fictional (made up). Does everything have to be an instruction manual, humorless, factual?

And, as we seemed to become more polarized on these topics, I remembered a clever poster that promoted reading. In one frame, a child is beginning a book about monsters. As he gets more and more “into” the book, he “becomes” a monster he’s reading about.

By the final frame, he’s back to normal. That illustrates the enjoyment of losing oneself in a book and of becoming a central character — a monster — if only for a few hours.

An editorial in the Santa Fe New Mexican laments the “throwing out (of) the teaching of literature in favor of nonfiction.” The argument is that the Common Core standards will ensure educational success to children who “were not reading enough rigorous texts.” One proposed facet to the Common Core is that 50 percent of elementary reading ought to be nonfiction, climbing to 70 percent by 12th grade.

If implemented as planned, most poetry would be tossed, along with many essential novels.

The Common Core, which by definition attempts to standardize the learning that students undertake in schools, can be a useful educational change. It would be beneficial if education developed a curriculum whereby students across the United States would study, for example, a few dozen classics, thus providing a common ground. And of course, using their own creativity, teachers ought to be allowed to supplement the reading core with items of their own choosing.

When I stressed this point — by this time my new acquaintance and I were both on the donors’ tables at United Blood Services — the gentlemen became adamant: “What does a kid in the Southwest care about maple trees in New Hampshire? Or a New Yorker know or care about adobes?” He had a point, and he kept fishing for a word to clinch his argument.

“Are you thinking of ‘relevance’?” I asked. He was. As a reader who is become more voracious as I age, I flatly disagree that we New Mexicans learn best when we read mostly about things already familiar to us: haciendas and hogans, posole and pinon, mariachis and menudo. I prefer that we BROADEN our knowledge of things around us — and even things far from us.

I don’t think my fellow blood donor appreciated how I ended the discussion, by citing one of William Shakespeare’s works, “King Lear.” It’s a play about an aging king who asks each daughter to declare her love for him. On the basis of her superlatives, the king promises to carve out choice parcels of his kingdom.

It becomes a contest in which the expected “winner” conjures up hosts of terms to describe the love she had for her dad.

“When it comes to relevance, to reading mainly about things within our narrow realm, then I guess we shouldn’t pick up a copy of “Lear” unless we’re 80, blind and have three daughters, two of whom are deceitful.