what is the opposite of linear?

The short answer is 'all at once."

But the long answer is "Nothing...There is no conveyor belt, Neo..maybe not even a line on the horizon..or a line anywhere."

Maybe even the "time working backwards" that George Ladd and Bob Dylan have commented on is an illusion.

I love Leonard Shlain, and pray he's doing well.

He would be a great guy to sit down with Bono, and talk art and physics.
Shlain might dare to suggest, though, that the shapeshifting Holy Spirit, hole-in heart, gal from Fez may have given a bit of bad physics advice to
the French motorcycle cop in 'No Line on the Horizon:"

It would seem that it's space, not time, that's truly not linear.

Space...and math/physics...and the nose... appear to be left-brain function...and somewhat logical and linear.
Time....and music....and the eyes.. appear to be right-brain functions...and pretty darn non-linear.

From Shlain's "Art and Physics":

whereas sight is largely holistic, all-at-once sense, the nose must process smells one-at-a-time...The right hemisphere of the brain is best able to apprecoiate these states (visual, contemplation) since the right all at once brain is older than the left one at a time brain...The right side specializes in the simultaneous coordination of information in space, while the left side collates data percived sequentially in time. This arrangement forces on dual-brained humans the illusion that reality is a series of casual events that appear in three- dimensional spatial extensions in a specific sequence..

All the innovative features of the left hemisphere--doing, words, abstract thinking,a nd number sense--are principally processed in time.. Time's function in speech is evident because language can be understood only if one person is talking at a time....By contrast, we can listen to all the instruments of a 70-piece orchestra's simultaneuous sound and hear them holistically, all at once....The four key features of the right brain are holistic...Music demonstrates the ability of right brain to process information in an all at once manner.
-Shlain, "Art and Physics",chapters 26, 27

Of course, this means that the woman in Bono's song, by virtue of appearing in a song, is in her right brain and right mind.
So maybe her advice is good after all.

And as a woman of the future (oops, spliced a song), she might like to overhear Shlain quoting William Blake: "Time and Space are Real Beings, a Male and a Female. Time is a Man, Space is a Woman."

Only women in space can comment prophetically about men in time.

And do it all at once, too boot.

No wonder she stuck her tongue in his ear, and messed him up for the rest of the album.

--

New York Times
Book Review:
"Provocative...passionate...Shlain points out uncanny parallels between the visual representations of artists and analytic representations.... He is an engaging story teller, skilled in the use of metaphor, analogy and even imaginary journeys that at times are poetic... Dr. Shlain's discussion of artistic images and his demonstrations of how these images can be used to describe the impenetrable ideas of physics are important."