Abduction

As mentioned in the blog of my friend Christopher Ecclestone entitled The Dig at the Daphne Bridge (May 22, 2010) the old Daphne Bridge over the torrent Phyrminus in Antakya has been unearthed in connection with canalisation repair. At that site last night I had an interesting experience that reveals how the human mind works.

We were on our way home after an Arabic coffee (served in Turkish tea glasses and called suvari) at the nearly historical coffee house Affân. When we passed the place of the old bridge one of our friends asked me: “They say that this is a tunnel used by smugglers that takes you to the other side of the Syrian border. Is that true?“

It should be mentioned that the distance to the Syrian border is about 50 kilometres. There are mountains part of the way. Those who within the last couple of months invented the myth of a smuggler tunnel never bothered to explain to themselves how it would be possible secretly to make a tunnel all the way to Syria when the government spends millions of lira to have a tunnel made through 5 kilometres of mountain other places in this country.

This brings us to how our mind works. When we know everything about a matter we are able to draw conclusions about singular aspects of this matter with the same certainty as you have about the whole. Example: 1. All humans are mortal. 2. The president is a human. > The president is mortal. This is called deductive reasoning.

Most often we do not know all the details about a certain question, but we know sufficient to have an opinion. 1. Some banks do crack. 2. This bank has never had any financial problem and as far as I can tell it is economically sound. > It is unlikely to crack. I can safely deposit my money there. This is called inductive reasoning. As we are not omniscient this is the reasoning we base most of our informed decisions on. It is also our basis for scientific theories and for religious faith - if we happen to base our faith on reason at all.

The third “discipline” is abductive reasoning* described by the logician Charles Sander Pierce as guessing. You could call it jumping to conclusions. In your daily life you are suddenly faced with something new and surprising, something for which you have no rational explanation. You do not have any premises to base your deduction or induction on. So you simply try to find an explanation on the basis of what the new experience looks like in comparison with what you have seen or heard before.

When you take a look at the old bridge across the Phyrminus as shown on the picture in the blog cited above it looks like the entrance to a tunnel because you do not see the other side of the bridge. In fact, had it been a tunnel its direction would lead you away from Syria, but the myth-makers did not think of that. On the other hand: Who are using tunnels? Smugglers are. Where do smugglers from this neighbourhood go? They go to Syria. So this must be a smuggler tunnel to Syria although it is leading you in the wrong direction.

We are such stuff as myths are made of.

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* Abduction

allows inferring a as an explanation of b. Because of this, abduction allows the precondition a to be inferred from the consequence b. Deduction and abduction thus differ in the direction in which a rule like "a entails b" is used for inference. As such abduction is formally equivalent to the logical fallacy affirming the consequent or Post hoc ergo propter hoc, because there are multiple possible explanations for b. For example, after glancing up and seeing the eight ball moving towards us we may abduce that it was struck by the cue ball. The cue ball's strike would account for the eight ball's movement. It serves as a theory that explains our observation. There are in fact infinitely many possible explanations for the eight ball's movement, and so our abduction does not leave us certain that the cue ball did in fact strike the eight ball, but our abduction is still useful and can serve to orient us in our surroundings. This process of abduction is an instance of the scientific method. There are infinite possible explanations for any of the physical processes we observe, but we are inclined to abduce a single explanation (or a few explanations) for them in the hopes that we can better orient ourselves in our surroundings. (http://en.wikipedia.org/wiki/Abductive_reasoning)