Wednesday, August 5, 2015

Effective Mandela Theory


There are at least hundreds of thousands (or even millions) of people around the world who were shocked to hear that Nelson Mandela died recently.  Their shock wasn't that a world-famous civil rights advocate had passed away.  They were shocked because they thought
the man had died thirty years ago!

According to an impressively large number of people, Nelson Mandela originally died back in the 80s when he was in prison.  They remember seeing it on the news and hearing about riots that broke out all across South Africa.  It's a very specific memory, and a lot of people share it.  It didn't happen (apparently, anyway), but thousands and thousands of people insist on remembering Mandela's death in prison and the resultant riots, and their accounts are fairly uniform (as uniform as memories ever are, anyway).

Now, people misremember things all the time.  And usually, people can be pretty stubborn about what they remember, especially when it's two memories against each other.  But when presented with something like every single newspaper ever printed that contradicts their claims, most people relent and admit that they're wrong.  With Nelson Mandela's death, the people who swear he died earlier believe this memory so strongly that they will not let go of it, despite being contradicted by every relevant fact in existence.  It isn't because they're just that stubborn, or that stupid.  The memory has a certain quality to it.  For whatever reason, their brain refuses to discard it.

This sort of phenomenon has become known (for better or worse) as the Mandela Effect.  It is when a large number of people share and insist on a fairly cohesive counterfactual memory.

Saturday, July 18, 2015

The fallacy of 'billions of billions', or: Why popular arguments that aliens must exist are bogus.

The universe is an awfully big place.  Granted, most of it is empty space.  But within that empty space, there are trillions of stars.  Maybe more.  At least some of those stars have planets around them, and some of those planets are the kind that could give rise to life.  That's still hundreds of billions (at least) of planets that can support life out there.  And so, the popular argument goes, even if the odds of life arising on another planet are very small, there are so many planets that it is bound to happen.  Thus, there almost certainly exist extraterrestrial life forms.  It isn't a matter of if, but of when we find them.

Here's a video of Dr. Carl Sagan presenting a more sophisticated version of this (with actual numbers) to estimate the number of inhabited planets in our galaxy.  Or try this worksheet on the Drake Equation on the BBC website.

It's a common argument.  And it sounds pretty convincing.  If you keep trying over and over, even though something is unlikely, eventually you will succeed.

It's common and convincing, but it's also fallacious.  Here's the problem: How many times do we have to try before we're guaranteed to succeed?

The mathematical answer is infinitely many times.

Saturday, March 21, 2015

Faeries in Phase Space

A few weeks ago, Professor Ben Zuckerman spoke at my school. He is one of the editors of the popular book "Extraterrestrials: Where Are They?" which explores in part the Fermi paradox: Why haven't extra-terrestrials tried to contact us yet? While he gave two lectures, I only attended one, where he went over many of the ideas in his book, explaining the rarity of technological life and the improbability of us ever making "contact".

I went to the colloquium talk rather interested. In honesty, I kind of misunderstood the intention of the talk (I thought he was going to be arguing against the existence of extraterrestrial life), but I was not disappointed. There were a lot of interesting ideas brought up about how to make contact or about what sorts of development projects we should pursue. And while I think some of them were really bad, they were thought-provoking. (Dr. Zuckerman of course recognizes the flaws of these, saying they are just stage 1 prototype designs).

The talk was very well done and I won't touch on it too much. What I really wanted to address was an audience question asked by one of the professors at my university. First let me provide some background.