Black Swans

The Black Swan metaphor refers to problems when it comes to drawing general conclusions from observed facts (and only from those observed facts). Meaning: if you see hundreds of white swans, does that mean that all swans are white? Hume describes this as follows:

"That there is nothing in any object, considered in itself, which can afford us a reason for drawing a conclusion beyond it; and, that even after the observation of the frequent or constant conjunction of objects, we have no reason to draw any inference concerning any object beyond those of which we have had experience". Hume (1748).

Related to 9/11 the black swan effect brings up some interesting thoughts. After the attacks happened they looked somehow predictable. It doesn't seem very revolutionary or out of the box to attack huge buildings with a plane, hm? Well, now it doesn't seem so. Human beings enter knowledge gained after an event into the gaps they had when building earlier expectations of such events: hindsight bias

Thinking about future possible terror threats we tend to stick to the swans that we have seen before. Our security strategies might focus on "white swans", we are afraid of "white swans" and all our attention goes to "white swans". However, the thing that we should focus on is another black swan, like 9/11. Something that is completely out of the box and not related to anything that we have seen before.

If we are not able to do so, we can only hope that terrorists as well are oriented towards white swans.

Interestingly, the Black Swan is not just a metaphor: The first cygnus atratus was sighted in Australia. :-)