"I, Robot," the book, published in 1950, is a collection of nine short stories by the prolific science-fiction writer Isaac Asimov. The stories, most of them written during the 1940s, are a contemplation of the nature of robots and artificial intelligence, and of the problems that arise in a future world that has become dependent on robots for various forms of labor, from extraterrestrial mining to baby-sitting. Azimov's robots have been manufactured to operate in strict accordance with the "Three Laws of Robotics":

1. A robot may not injure a human being or, through inaction, allow a human being to come to harm.

2. A robot must obey orders given it by human beings except where such orders would conflict with the First Law.

3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.

The robots' human masters assume that these three built-in safeguards will preclude any possible problem, but they are profoundly mistaken. A robot, for example, might decline to tell its master the truth about a situation if it concludes that the truth will cause its master harm. More ominously, a robot might decide that a master's own behavior is harmful, and take action to alter that behavior. In addition, with technological improvement robots might eventually attain a state of "mind" approaching human consciousness; they might learn how to learn.

These are, of course, fascinating ideas, and to the extent that they survive in the new movie, "I, Robot," they are the most interesting thing about the picture. But while the film takes its name from Azimov's little classic, its story was in fact only "suggested by" the book. This new "I, Robot" actually started out more than 10 years ago as a script called "Hardwired," a robot murder mystery by screenwriter Jeff Vintar. Twentieth Century Fox eventually picked up "Hardwired," and put it into development in 2000 with the Australian director Alex Proyas attached. (Proyas was a perfect choice, having directed both "The Crow" and the highly regarded 1998 sci-fi thriller "Dark City.") Along the way, the film rights to Azimov's "I, Robot" were acquired, Will Smith was signed to star (and executive-produce), and he brought in Oscar-winning screenwriter Akiva Goldsman ("A Beautiful Mind") to synthesize a new story out of Vintar's original "Hardwired" script and Asimov's stories. As the "I, Robot" production notes put it, "Asimov's ideas and characters fit naturally within the structure of Vintar's mystery tale."

Well, maybe. Certainly only hardcore Asimovians are likely to object that the master's intricate philosophical inquiries are overshadowed by the action requirements of the movie. Some of Asimov's concerns -- about the limits of logic and the nature of consciousness -- are honorably preserved. But "I, Robot" is an action movie, clearly conceived as a big-budget summer blockbuster; and in movies like this, if philosophical ironies only crop up between omigod car chases and robot free-for-alls, well, you have to be grateful they're there at all. For the full Asimov effect, you can pick up the "I, Robot" book, which was recently reissued as a film tie-in. The movie, however, stands, or wobbles, on its own.

The setting is Chicago in the year 2035. Over the course of many decades, robots have become an integral part of the urban landscape, bustling about as spindly, metallic messenger boys and cheery deliverymen, among many other things. (Robots have no gender, of course, but their general bearing here is entirely masculine.) They are mild-mannered, unthreatening, and above all, helpful. When an asthmatic woman leaves the house without her inhaler, her robot sprints home to retrieve it. Just about everybody loves robots -- soon there will be one of them for every five humans. And that's okay; there's nothing to worry about, because a robot has never committed a crime. Ever.

Police detective Del Spooner (Will Smith) doesn't buy into any of this. Spooner is a techno-skeptic in general, and a robo-phobe in particular. The reason for this is a little odd: Spooner, it seems, was previously involved in a two-car collision, to the scene of which a passing robot rushed to provide aid. Spooner, seeing a young girl trapped in the second car, shouted at the robot to save her first; but since Spooner was more immediately salvageable, the robot, following the dictates of its programming, went ahead and saved him instead. The little girl died. This was a terrible thing, but as justification for an unbudgeable anti-robot grudge, it's a little hard to accept.

Spooner is especially wary of a new, "smarter" breed of robot, the NS5 model, which is just being introduced. His disquiet deepens when Dr. Alfred Lanning (James Cromwell), the pioneering research chief at U.S. Robotics -- the all-conquering Microsoft of the robot industry -- is found dead at the company's headquarters. USR chairman Lawrence Robertson -- whose goal is to put a personal robot in every home -- dismisses Lanning's death as a suicide, and his head "robot psychologist," the coolly corporate Dr. Susan Calvin (Bridget Moynahan), hastens to agree. But Lanning (who befriended Spooner while treating him after his accident) left behind a hologram of himself, and after consulting with the hologram, Spooner decides that Lanning was murdered, and he sets out to find the mechanical culprit.

This is a pretty interesting story, and a lot of time, talent, and money have been devoted to pumping it up. There are some wonderfully conceived scenes, like the one in which Spooner, confronting a room full of robots ranked in long military-style rows, spots one silvery head leaning out at the end of a line and then quickly ducking back in again, and he knows he's caught his culprit. (Or thinks he knows, anyway.) And you have to lightly admire the many kinds of expertise that went into creating the ultra-slam-bang chase scene in a highway tunnel in which Spooner's futuristic car (its ball-shaped wheels allow it to drive in any direction) is cut off and attacked by two huge trucks filled with vicious NS5s. Also impressive is the scene in which a giant destructo-bot tears apart a house that Spooner is investigating and nearly puts his boat-rocking suspicions permanently to rest.

This is all state-of-the-art wow, for sure. But there's something distancing and basically unsatisfactory about so much completely computer-generated action: When you watch one band of robots leap into battle with another, what you're watching, in effect, is a computer game, pasted up onto a very big screen. This has been a long-growing problem in the action-movie genre; here, I think, finally, it's a crucial flaw.

The director has managed to implant a heart of sorts into the hyper-digital proceedings: a lovable robot called Sonny (Alan Tudyk). Created by Lanning, Sonny has started to think of himself as an individual. ("I believe my father made me for a purpose," he says.) Sonny is at one point presumed to have murdered Lanning, and the scene in which he is led into a laboratory death chamber to be "decommissioned" is unusually moving. (He doesn't want to "die.") But however cleverly expressive Sonny may be, his expressiveness is still fundamentally limited by the fact that he is, after all, a metal-faced robot. And the filmmakers' claim, in the "I, Robot" production notes, that Sonny is "the most realistic, emotionally complete, three-dimensional CGI character ever created on film" is really astonishing. Have they never seen the second and third "Lord of the Rings" movies? Does the name "Gollum" not ring even a distant bell? (Ironically, Weta Digital, the New Zealand FX company that did such groundbreaking work on the "Lord of the Rings" films, also did some CGI work on "I, Robot." Not on Sonny, though, apparently.)

A common risk in big action-fantasy movies like this one is that the brain-bombing effects will overwhelm the merely human actors. This is especially a problem when the actors themselves don't present a whole lot to overwhelm. In "I, Robot," James Cromwell contributes a weary, much-appreciated warmth as Lanning. And Chi McBride, as Spooner's police-lieutenant boss, is believably, amusingly harried. But as the robot psychologist Susan Calvin -- a cold, hard industrial scientist in the Asimov book -- Bridget Moynahan is oddly fretful, denying the obvious at every turn, much in the hapless manner of Dana Scully in "The X-Files." (In one scene, she also wears a shiny, future-fashion suit of a sort that hasn't been seen since the obliviously ridiculous space flicks of the 1950s.) And Bruce Greenwood, playing the USR boss Robertson, isn't given a whole lot to do beyond glower and fume, which, to be fair, he does about as well as it can be done. And then there's Will Smith.

Smith unforgettably rewrote the rules of the international action-blockbuster genre with his starring role in "Independence Day," in 1996. Up until that time, it was thought that a black actor couldn't provide enough box-office oomph to carry a big-budget production. ("Independence Day" went on to become the top-grossing movie of that year.) He was similarly winning, and very funny, in 1997's "Men in Black." But in "I, Robot," he seems to have settled into a type: the hip urban action dude of the future, with a slick wisecrack for every occasion. (Erupting into a loud sneeze in the middle of some corporate pro-robot spiel, he says, "I'm sorry -- I'm allergic to bullsh--.") Spooner is a totally, inexplicably retro guy. His Converse sneakers are "vintage 2004," his CD player is a JVC antique, and his musical tastes run exclusively to oldies, like Stevie Wonder's "Superstition." (Is there no happening hip-hop in the world of the future?) And while Smith has always been in obviously great shape, he's now so formidably ripped, it's distracting -- you wonder if maybe his muscles had a separate trailer on the shoot. (There's no real narrative reason we have to see his bare, buff behind, either, but I realize there'll be few complaints in this regard.)

Will Smith is a smart actor, and while he doesn't do anything dumb here, what he does do, he's done before, and more than once. And when just about everything else in a movie like this seems like it's been done before -- in "Terminator," in "Robocop," in "Minority Report" -- you keep hoping that maybe the star will surprise you in some zingy, non-digital way. It's surprising that Smith doesn't, this time. But that's the only real surprise in this over-computerized, under-humanized movie.