In my composition classes, we have a semester long conversation about what an essay is and how best to write different forms of essays. Alan Lightman, in his introduction to the Best American Essays 2000, puts it pretty succinctly:
“When I’m reading a good essay, I feel that I’m going on a journey. The essayist is searching for something and taking me along. That something could be a particular idea, an unraveling of identity, a meaning in the wallow of observation and facts. The facts are important, but never enough. An essay, for me, must go past the facts, an essay must travel and move. Even the facts of the essayist’s own history, the personal memoir, are insufficient alone. The facts of personal history provide anchor, but the essayist then swings in a wide arc on his his anchor line, testing and pulling hard.
I suppose that in the end, the real subject of an essy is the essayist. Not the bald facts of autobiography, on the one hand, or the bald opinions about issues, on the other, but some kind of union between the inner person and the outer world, a melding of internal and external, the life and mind of the essayist in reaction to the universe. The essayist cannot examine the world without examining herself, and she cannot examine herself without examining the world.”