Se non è vero, è ben trovato: if it’s not true, it’s a good invention. It is no secret that the facts have rarely sullied a good film. In fact escapism is a significant desire of many film-goers. Every film – yes, even a documentary on some level – requires at least some suspension of disbelief. However by the same token it is important that there is a level of internal consistency. For example, most of us are happy enough to accept that we all might be hooked up to life support by aliens, and our conscious thoughts are really clever simulations on some grand computing system…but this is all done so the aliens can harvest the electrical energy given off by our bodies? Give me a break.
At this point the spell is broken. Once set up, the rules of the universe ought only be compromised with sufficient explanation or justification, else there is a serious risk of making the audience feel ripped off. Deus ex Machina (‘God out of the machine’) may have been fine for the Greeks. However we’ve come a long way since we passively entrusted Apollo to flutter down from the riggings to save our hero every time he got into a tight situation (you’re probably too young to remember JR Ewing being shot in Dallas, but I’m happy to give away that, a posteriori, it was all a dream). Although the supposedly sophisticated modern audience still gets ripped off left right and centre (movies that have audiences are businesses after all), the cleverer inconsistencies in films involving scientific issues often turn out to be examples of Fridge Logic/Science. This sophisticated class of inconsistency effectively tranquilises the most sceptical viewer until they’re well out of the theatre, musing the finer points with the fridge wide open, when the penny bounces back from whence it had supposedly found solid ground: “but … how could Keanau have outrun the fusion blast on that crappy motorbike?”
Anyone with a hint of a scientific background is at constant risk of nerdy blackguardism if they point out each time someone should have had their shoulders dislocated from swinging many stories on a thin rope, a car exploded without containing an explosive fuel-air mixture, or a lead bullet created a spark upon a ricochet. The more nuanced films short-circuit the potential for widespread disbelief through the dark art of Lampshading. This clever trick, where the logical or scientific impossibility is explicitly acknowledged, is common in time-travel films such as Terminator 2: Judgment day (1991), wherein the young John Connor muses: “My Mom says when I’m, like, 45, I think, I send him [his own father] back through time to 1984. But right now he hasn’t even been born yet. Man, it messes with your head”. Ahh, that’s great, because it was messing with my head too! This acknowledgement just made me feel better about the whole thing, even if it was merely a vague implication that someone much smarter and with better data than me actually knew what was going on.
So most of us would resent paying our valuable money and time to sit in a movie theatre to get an education (we prefer to pay far more for education). Occasionally we will accidentally be educated on some scientific issue, once our minds have been kneaded into a sufficiently vulnerable state. This is where the exposition segments begin, such as a convenient news-flash (invariably with uncanny timing), a film shown in class, or perhaps a lab-coated boffin shambles the viewer awkwardly on a tour of The Shiny Facility.
We will happily accept many minor transgressions. For example, it is well known that the sound of most distant explosions won’t reach us at the same time as the light does; there should instead be a delay of about three seconds for every kilometre away (although shock-waves can discount this slightly). This fact is conveniently circumvented too many times to mention here. Yet, to be faithful to physics, our hero would just look like a jerk running around in near silence trying to take shelter from a distant abstract light, while the bored viewers can hear every chump in the other pews eating their popcorn. So we forgive this imprudent trope. As we can with e.g. thermal imaging devices that can magically form images through walls (Blue Thunder, 1983; Predator 2, 1990), clones being the same age as their originals (The 6th Day, 2000) or Conservation of Mass violations (Transformers, 2007), Honey I Shrunk the Kids (1989), The Incredible Hulk (2003 and 2008). The Starship Enterprise blithely cruised through space-time geodesics that only seconds before were curved enough to compost an entire planet (Star Trek, 2009) and I didn’t bat an eyelid. For these grievances we willingly sacrifice scientific accuracy because they either look/sound good or move the plot forward in an entertaining way.
However, some blunders have no good justification and, like a teenager separated from their cell-phone, cry out for a re-write. We’ve become so awed by manipulation of digital imagery that numerous films take liberties beyond the possible, obtaining extra-dimensional information from cameras, such as the ‘enhance and rotate the image’ scene from a lone security camera in Enemy of the State (1998). Or aliens that have an Achilles’ Heel on Earth that their advanced technologies detected failed to detect until their demise (particularly egregious in Signs, 2002). I don’t really need to beat up any more on The Core (2003), whose carcass has been mutilated by too many before me. This level of flaw would have been made both more plausible and more interesting with a simple re-write.
Considering the above, slick tropes and real science notwithstanding, you might think that most scientists would be offended by all the ignorant applications of bad science in a film. Au contraire! Many of us quite enjoy such sport (despite usually being single player) and there is only one tool required: the Fermi Calculation. The famous Italian inventor of the nuclear reactor, Enrico Fermi, was renowned for making rapid back-of-envelope calculations that were surprisingly accurate, considering the very limited data used in the calculation. A quick Fermi calculation lends itself surprisingly well to an adequate verification of some science in films. Fermi Calculations of a range of films are given in a neat paper by Costas Efthimiou and Ralph Llewellyn from the University of Central Florida (here and here). They show that in Amageddon (1998), even generously overestimating the yield of the nuke used, that bits of the antagonist (a huge asteroid) would only have moved ~250 m off its original trajectory by the time it pulverised some part of the Earth.
So to conclude with an answer to the original question: how necessary is scientific plausibility in film? In the case where the suspension of disbelief is a conscious and constant issue, it is vital. It will be difficult to watch such a film. However, in most cases, we can sacrifice a few misgivings if we know that it is for the betterment of the story, or it merely looks good without doing too much harm.
About the author
Ra hitch-hiked out of the West Coast of the South Island of New Zealand to become a physicist. He got his PhD in Guitar Acoustics and, after looking at how termites use acoustics to communicate, currently looks for vibrations in the very fabric of space and time. He has directed two short films, enjoys writing and likes to play guitar.