McWilliams, a historian at Texas State University, has made challenging the mores of the organic, slow food, eat local movements his life work. The title of his last book: “Just Food: How Locavores Are Endangering the Future of Food and How We Can Truly Eat Responsibly,” is sufficiently illuminating. This time out, his argument is straightforward: The reaction against “industrial food” is just another time-honored manifestation of an American infatuation with a simpler life.

For all their moral impact, our linear jeremiads fail to capture the circularity of history. This is especially true with our back-to-the past reaction to “industrial food.” Current calls for dietary simplicity might have a revolutionary ring to them. But what’s overlooked in all the enthusiasm is this: Americans have always idealized, or at least harkened back to, an agricultural era when production was supposedly simpler, closer to the land, and unadulterated by the complexities of modernization. What we’re seeing right now with the food movement is, for all its supposed novelty, a stock (even banal) reaction to broad historical changes.

Wow: “curious,” “entertaining” and “banal.” That’s quite the triple play. I imagine McWilliams observing the customers at a Berkeley farmer’s market with the bored half-smile of a late 18th century French aristocrat gracing his face. Ah, the native customs here, their very quaintness makes them both fascinating and so very, very dull!

I will grant that Americans have an undeniable tendency to idealize “mythical golden ages” and McWilliams does a good job of unearthing outbreaks of such longing, as they pertain to food, going all the way back to James Madison. But this emphasis on the circularity of history plows directly into a paradox: By dismissing those who are currently pushing for healthier food and more sustainable agriculture as “primitives” he is making an implicit argument against another core American belief — our faith in progress.

Michael Roberts, an economist who specializes in food issues, touches upon this issue in his own response to McWilliams:

The difference between today’s movement and the past is that we have data that show real costs to health stemming from cheap and highly processed food. The obesity crisis is real. Growth in diabetes is real. The broader causes are pretty clear.

That’s right. Science. Michael Pollan’s pithy manifesto — “Eat food. Not too much. Mostly plants” — isn’t a reaction against modernity; it’s a consequence of the human ability to probe the mysteries of the universe and learn how things work. It is rooted in science, the outcome of our ever-advancing understanding of biology and chemistry and nutrition. If the course of the Industrial Revolution proves anything, it is that history is not circular. We are hurtling into the future at high speed and making lots of mistakes as we do so. But we’re smart critters and we can learn from our mistakes and fix things as we go. (That’s the theory anyway — the 21st century may yet prove me wrong.) There are health implications to eating too much processed or junk food, and there are environmental implications to industrial agribusiness, and there are always better ways to do things.

In her review of “Just Food” for Grist, Stephanie Ogburn wrote that “Again and again, one gets the uncomfortable feeling that McWilliams creates fanatical straw men in order to make his own presentation of facts seem like a rational alternative.” That’s exactly what he’s doing at Freakonomics, and it is neither curious nor entertaining. But it is predictable contrarianism, so I guess it qualifies as banal.

Too bad the machine doesn’t actually exist. What many bloggers missed is the fact that the Cornucopia is still only a “concept design” — an idea with a digital rendering, and not much more. Amit Zoran writes via e-mail that, although the pair have worked on some “applied tests and controllers,” the machine “isn’t much more than sci-fi.” But, as the Internet hype shows, it’s a fantasy that holds broad appeal — and, given some recent advances in technology, may be more feasible than you’d think.

In recent years, 3-D printers and scanners — machines that create digital models of objects, and then build them on the spot in three dimensions using a special kind of printer — have become smaller, more user-friendly, and more widely used. They can now been used to create television and car parts, replicas for museums, 3-D sculptures — and, in some cases, food.

In 2007, a group called Evil Mad Scientist Laboratories created something called the CandyFab, a 3-D printer that creates elaborate shapes out of sugar. The CandyFab is a DIY project — it’s open-source, uses recycled material, and costs less than $ 500 to produce — and works by fusing together layers of sugar. The machine prints one two-dimensional design, then prints another design on top of it, fuses them — and continues until a three-dimensional shape emerges. Among the project’s accomplishments: Printing a gigantic sugar screw, and creating beautiful mobius-strip-like sculptures.

And in the past few months, Dave Arnold, the director of technology at the French Culinary Institute, has been experimenting with a 3-D printer called Fab@Home. The machine, which is on loan from Cornell University, creates three-dimensional objects by discharging materials from two 10mL syringes (meaning the ingredients used have to be in homogeneous paste form, and the final product can’t be any bigger than a pound of butter).

The Fab@Home can create highly intricate shapes on the inside of foods, and so far he’s used the machine to create, among other things, multilayered meatballs (“essentially a filling inside a filling”), and small space shuttles made out of scallop paste. As he explains on the FCI’s blog, he’d like to be able to create “little food creatures that move under their own power,” and he told me over the phone that he wants to make a dish using “alternating layers of paste, including fibers like meat” that would be too difficult to make by hand.

But the experiment so far hasn’t lived up to Arnold’s hopes. “I want to get something here that’s valid from a culinary standpoint. We want to try to find an application where the food we’re making is actually better than any other technique we can use,” he says. Much of what he’s produced thus far is more easily made using other techniques — especially on an industrial scale. (It’s much faster to create 1,000 scallop-paste space shuttles using a mold than it is to print them out a 3-D printer.)

Clearly, a number of obstacles will still have to be overcome before a machine like the Cornucopia  can become reality. Existing fabricators can’t heat, season or bake any food (much less create a steak dinner from scratch), and, from a cultural standpoint, the idea of a 3-D printer runs counter to some of the major trends in American eating — which are emphasizing fresh, locally grown, minimally processed ingredients. That said, it’s not hard to imagine 3-D printers being used in the creation of manufactured foods, like custom high-end candy or chocolate, in the near future.

But even if the Jetsons experience becomes reality, claims Arnold, it may not be a good thing for American eaters. “For me, the entire idea of reducing the eating experience to a printout seems bizarre,” he says. “If you actually think you’re going to print out all of your food, you don’t like food.”