Keith Hennessy in “Crotch.”Credit..

Keith Hennessy in “Crotch.”Credit...Andrea Mohin/The New York Times

Yet everything in this work was ambiguous. The men were remarkably relaxed, dispassionate; and the slowness acquired its own cool rhythms. While Mr. Johnson and Mr. Asriel parted their legs, shifted their pelvises, rippled their spines, new contours and alignments of their musculature would emerge. The interest was heightened by their physical disparity. One had more muscular firmness and definition, the other more softness and linear flow. New connections of shapes and lines in abdomen, back, pelvis, thigh, different in each case, emerged continually.

My point is not to single out Mr. Jasperse as a great artist amid a field of awkward experimentation; I have liked other pieces by him much less. I mean simply to show that works of serious art can occur in situations where moral and aesthetic considerations are complex; the effect of good art is to make them only more complex. Among other things, “Fort Blossom revisited” showed how the erotic and the unerotic can coincide bewilderingly. Those movements and positions for the two men: were they sexually hot or cold? Scientifically objective or personally revealing? The answers kept changing.

I‘ve mainly been using the word “naked” rather than “nude.” The art historian Kenneth Clark began his beloved book “The Nude” (1956) with a distinction. “To be naked is to be deprived of our clothes and the word implies some of the embarrassment which most of us feel in that condition,” he wrote. By contrast, the image projected into the mind by the word nude “is not of a huddled and defenceless body, but of a balanced, prosperous and confident body: the body re-formed.”

Clark knew and loved ballet. And I believe that what underlies ballet is the same ideal that underlies the nude. Ballet’s heroes and heroines wear clothing, and yet they deploy lines, positions and phrasing so that they too may project an image of the body as perfectly harmonious and apparently flawless. When you watch a prima ballerina in her tutu, her tights, her point shoes and — more relevant — her arabesques and her fifth positions, you see crucial aspects of the traditional nude. In her, you see the body balanced, prosperous, ideal, radiantly unembarrassed.

This paradox was taken further by Arlene Croce in a 1974 review in “The New Yorker” when, discussing the illusion created by ballet, she wrote, “The arabesque is real, the leg is not.” Anyone who loves ballet will recognize the rightness of this.