What We Now Know to Be True

Dr. Melik: This morning for breakfast he requested something called "wheat germ, organic honey, and tiger's milk."
Dr. Aragon: Oh, yes. Those are the charmed substances that some years ago were thought to contain life-preserving properties.
Dr. Melik: You mean there was no deep fat? No steak or cream pies or... hot fudge?
Dr. Aragon: Those were thought to be unhealthy, precisely the opposite of what we now know to be true.
Dr. Melik: Incredible.
Sleeper

So you've got this great idea for a science fiction story. There's just one problem: an element of the story is blatantly contradicted by a piece of actual science, and you don't want it to look like you honestly didn't know this.

But wait! Science Marches On, right? Science is always evolving, and sometimes what we thought was certain turns out to be incomplete or incorrect. So in a story involving people from the future, ahead-of-their-time scientists, or Sufficiently Advanced Aliens, one way of getting around a scientific inaccuracy is to mention the current theory... and then have one of the characters dismiss it as an outdated misconception.

This serves as a quick Lampshade Hanging which acknowledges the departure from the facts, and allows you to get on with the story. This kind of dialogue can also be used when the science itself is in a state of flux at the time of writing—the characters discuss the competing theories, and whichever one "was proven accurate" is the one taken as accurate in the story, whatever happens later in Real Life.

This trope can also be Played for Laughs, especially when the difference from real-world science is ludicrous: "People in the twenty-first century used to think that? They must have been really stupid!"

Compare Outgrown Such Silly Superstitions (for cases involving cultural or relgious ideas rather than scientific ones) and Necessary Weasel (for cases where ignoring some inconvenient real-world restriction has become a standard part of a genre).


Examples:

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    Film 

    Literature 
  • In Journey to the Center of the Earth, Axel expresses concern that the adventuring party will encounter great heat and pressure in the interior of the Earth, which will probably kill them. Professor Lidenbrock argues that the heat will not be great, and they will be able to acclimate to the pressure. He's right.
    • In fact, this was a popular theory in the days of Jules Verne: that the only thing that happened as you get closer to the center of the earth is that pressure continued to increase, until you would eventually get to a point where the pressure was so great that the air itself was forced into solid form, representing the core. It was based on this theory that he wrote the story.
  • In Lucky Starr and the Oceans of Venus (written in 1954, before astronomers had a clear idea of what the surface of Venus was like), Lucky mentions that "until the late 1900s astronomers thought Venus had no water. When ships began to land, mankind found that wasn't so."
  • In a Discworld book, Vetinari comments how centuries ago they thought the Disc was round, but now it's a scientific fact it's a disc on the back of four elephants standing on a giant turtle.
  • The advanced aliens in the Uplift universe have nothing but contempt for the Earth concept of the continuum, and thus for any science not based on discrete mathematics. This may be justified, since even some contemporary Earthlings regard the continuum as a useful shortcut that we can forget about once we have sufficient computing power.
  • Atlas Shrugged: Galt's engine is called out as working on a new principle and proving several laws of physics to be false. Unkind people have suggested it harnesses the power of Plot.
  • In one of the Animorphs books, the alien Ax is looking through the other Animorphs' text books and comments, "That's not how gravity works at all."
    • Although, modern physics is still working out how gravity works on a quantum level.
  • Many, many, many science fiction stories that have some form of Faster Than Light Travel will include some reference to (Scientist) who discovered the theory which superseded Relativity, and thus allowed faster than light travel.
  • Oddly enough, this sort of reasoning is sometimes used in actual science textbooks (usually when the writer themselves hasn't checked the facts and is just repeating the popular view). A good example is in biology where What We Now Know to Be True is that Pasteur "disproved" the theory of spontaneous generation. Actually, he didn't. Not conclusively anyway, and he hid some of his results according to the article.
  • Done in Call Me Joe, where Jupiter turns out to have a solid surface.
  • Matthew Joseph Harrington uses this gag a few times in the stories he wrote for the Man-Kzin Wars series: lung cancer was discovered to be caused by a virus, not smoking, and the asteroid that killed the dinosaurs hit Iceland, not the Yucatan.
  • In The Giants Trilogy, we discover that conservation of energy isn't entirely true - there are ways to produce free energy.
  • The Frank Herbert novel The Dragon in the Sea was set on a futuristic submarine where vacuum tubes were a plot element. A named but unspecified 'effect' was used to justify their not having been replace by transistors.

    Live Action TV 
  • The Tollans, an advanced human civilization in Stargate SG-1, have studied quantum physics... "among other misconceptions of elementary science".
  • Doctor Who, "Shada":
    The Doctor: What? Do you understand Einstein?
    Parsons: Yes.
    The Doctor: What? And quantum theory?
    Parsons: Yes.
    The Doctor: What? And Planck?
    Parsons: Yes.
    The Doctor: What? And Newton?
    Parsons: Yes.
    The Doctor: What? And Schoenberg?
    Parsons: Of course.
    The Doctor: You've got a lot to unlearn.
  • Blake's 7 pulls a two-for-one example in the pilot episode, when the cast discover that their newly acquired spacecraft goes really, really fast:
    Blake: You mean we crossed the antimatter interface? That's impossible.
    Avon: That's what they said about the light barrier.
  • In an episode of The Outer Limits (1995), some visitors from the future arrive and meet some present-day scientists. When the one of present-day researchers mentions time-dilation to a visitor she's chatting with, he winces a bit, although he doesn't correct her assumptions because he can't afford to change history by telling her where her ideas are wrong.

    Webcomics 

    Western Animation 
  • Often played for laughs on Futurama:
  • Time Squad is set in a future where there's no more war, no more pollution, humans have cracked time travel and bacon is good for your heart.