Showing posts with label perpetuum mobile. Show all posts
Showing posts with label perpetuum mobile. Show all posts

Sunday, March 9, 2014


I have become accustomed to using the word "anti-paradox" to describe a particular kind of time travel oddity.  I first encountered this word either on Wikipedia or TVTropes (sometimes it's hard to tell).  Now, despite my constant searching, not only can I not find the original article, but I cannot find any article anywhere on the internet using the word in the way I remembered seeing it.  The definition, as near as I can remember it, is as a follows:

An anti-paradox is a self-supporting, self-validating, tautological statement or situation.

It is a statement that is true precisely because it is true.

One of the examples that the article gave was the Robert A Heinlein book, "All You Zombies".   But that plotline is convoluted, and gross, so let me give a simpler example of a time travel anti-paradox.

A man is sitting in his room.  Suddenly, in a whir of sound and light, a metallic box appears in the room with him, and out steps an elderly gentleman.  The elderly fellow explains that this box is a time machine.  The elder has finished with time travel and wants to end his days as he remembers them before he left; and so, he is giving the machine to the younger man.  The younger man takes the machine and travels up and down the timeline, meeting famous people from history and exploring the technology of the future.  After decades of time travel adventures, saving the world from evil robot kings and stopping the Eiffel Tower from collapsing (he succeeds), the man becomes tired.  All this moving.  He wants to stop, and find some time, and just stay there.  But the only time he really remembers having any attachment to is the time before he left.  And so he returns to that day when he first got in the machine, and hands it off to his younger self, and stays there in his own time until such runs out.

This situation is an anti-paradox.  The man gets the time machine because he has the time machine because he gets the time machine because he has the time machine.  The attainment of the time machine is the cause of its own attainment.

This isn't contradictory, nor does it even offer an apparent contradiction.  It might be more correct to say that it makes too much sense.  The "problem" with it is that it doesn't have any exterior input.  No one builds the time machine.  The man has a time machine because he has a time machine.

I distinctly remember reading this situation as being called an anti-paradox.  Can anyone corroborate this?

If not, then let me propose the word for general use.  Anti-paradox: a self-supporting, self-validating tautology.

Saturday, December 22, 2012

In Defense of the Perpetuum Mobile

Somehow, I stumbled on a series of YouTube videos on perpetual motion machines.  They are very fun.  The videos mainly consist of two types:

  1. Scammers looking for a laugh trying to trick gullible people into wasting their time building them, though secretly there will be a hidden engine or off-screen fan providing additional torque to the device.
  2. The people who fall for these scam designs, and their own self-imposed scam designs, who are honestly trying to build a perpetual motion machine and honestly think they have built a machine that runs forever.
You get a lot of failed designs, obviously.  Technically, you get all failed designs.