Screen test

Starting tomorrow, The Independent – in association with Empire magazine – will be publishing four separate guides to the most influential science-fiction, crime, comedy and action films of all time. Designed to be dissected and argued over, the venture raises interesting questions about what makes a film influential, and why. Are all influential films necessarily great? And are all great films also, by the very nature of their greatness, influential?

A film can, of course, be patently ridiculous albeit pleasurable nonsense, such as Star Wars or Dumb and Dumber (both make Empire's lists), and still be massively influential, while another film can be an obvious masterpiece, but manifestly not influential since hardly anyone has ever seen it, such as... (insert the name of your favourite little-seen art-house masterpiece or straight-to-video schlock here). Personally, I'd plump for either Todd Haynes' banned short film Superstar: The Karen Carpenter Story, or the cartoon feature The Brave Little Toaster.

These lists were not scientifically devised, but you can bet that whoever drew them up meant them to encompass movies that were popular and exemplary of their genre, that affected the film industry in the long run, and were eminently rip-off-able. After all, a film's influence – even a film's greatness – is measured by its imitators, as well as by its satires and its sequels. Thus, you can quantify the influence of Blade Runner by the number of wannabe "Blade Runners" of varying quality out there cluttering up the video stores: Dark City, Cyborg, Johnny Mnemonic, The Fifth Element – they are legion. Of course, a film such as Blade Runner had its own set of progenitors: films noirs of the Forties, with their trench coats and lashings of rain, and the dystopian visions of future cityscapes seen in Metropolis (which also makes the list) and Things to Come (which doesn't).

Cinema is only 100-and-a-handful years old. Vast swathes of its history are available for home viewing, or at least partly archived, so the medium exists in a perpetual present, where everything has potential to be influential because almost everything is instantly available, like a vast electronic network that's always switched on. It's an interviewing cliché to ask a director what his or her influences were, but still journalists keep asking the question, because you get such bizarre answers. One journalist I know asked the Italian horror meister Dario Argento about films that inspired his own lurid gorefests. He said that he had learnt everything about colour from Disney.

Some films are obviously more influential than others, but which ones endure as icons is just as subject to shifts and fluctuations in taste. Empire's list is inevitably a reflection of what looks influential "now". When one of their comedy choices, This is Spinal Tap, came out in 1984, its fake documentary aesthetic looked like an inspired oddity. Now the "mockumentary" is practically a genre in its own right, the template for Bob Roberts, the TV series The Office as well as the Tap team's latest film, A Mighty Wind. Film culture shifts, and what were once considered classics are now aesthetic dinosaurs. Director David Fincher (Fight Club, Panic Room) recently remarked that "Casablanca now feels like a stage play. It's beautifully, classically made, but in terms of the language of cinema, it's almost irrelevant."

To attempt to map out which movies have been the most influential might be doomed as a perpetually quixotic project, but it's one that gives us at least a fleeting sense of mastery over cinema's teeming, vast multiplicity. Like the Swedish botanist Linnaeus back in the 18th century, divvying up the plants in his garden and thus forming the basis for modern biological classification, we group and class and regroup the key films from cinema's history, hoping the process will create a taxonomy that makes sense of the whole tangle. Such a project at least aspires to understand how films relate to one another, rather than suggesting which films or stars or first assistant directors are "the greatest". After all, where would biology be today be if Linnaeus had preoccupied himself, in his back garden, with the "greatest" plants?

Take part in our online quiz and win £150 of vouchers