03 Dec Logic, reasoning and the autistic mind
Logic. For many an unexplored territory, for some a necessary evil, for few a great working field. Most people don’t know that logic is more than letters, arrows and scary little hats. Logic has many facets and thereby connects a lot of disciplines. I’ll take you through one very interesting example of logic, human reasoning and autism spectrum disorder.
Praise the Lord, we’re irrational!
According to Aristotle and many great thinkers after him like Bertrand Russell, there is only one way to reason correctly – through the laws of logic, which cover all rules we are “permitted” to use. Humans however don’t always reason through these laws, due to mistakes and limited brain capacity. We are irrational and therefore wrong. You don’t believe me? Give it a try!
But this “irrational” behaviour isn’t always wrong. Suppose someone says to you: “if you turn the key, the car will start” and you turn the key. Will the car start now? According to the very old reasoning rule modus ponens, you should always infer that the car will start, period. No exceptions.
However, everybody knows that our example car might not start in real life. That’s because you have access to prior knowledge and experience, or new facts that suddenly arise. Maybe it’s cold, and you think back about that cold day your car had starting problems, or someone might just tell you that your battery is low. Using this knowledge, you might come to the conclusion that there is no guarantee that the car will start, although you did turn the key! In short: you know you’re dealing with the real world and you reason accordingly – not undesirable at all!
The form of reasoning that takes additional information into account is called non-monotonic reasoning. Exactly this type of reasoning is impaired in people with autism spectrum disorder (ASD). ASD is the new term encompassing autism, Asperger’s syndrome and PPD-NOS. People with ASD often have difficulty with unexpected events and changes. Therefore, they also find it hard to deal with exceptions to regular reasoning; they have problems to reason in a non-monotonic way.
This link between ASD and reduced non-monotonic reasoning can be seen in the suppression task. In this test, people have to finish a reasoning task (such as our car with its key) while confronted with new information (such as the cold weather outside). People who don’t suffer from ASD often change their conclusions in the light of this new information, while people with ASD often stick to the original conclusion.
Back to logic
But what is the connection to logic? Well, the laws of logic I talked about before are just the laws of so-called classical logic, but that’s not the only logical system there is! Your non-monotonic reasoning can for instance be described by non-monotonic logic. Using this logic, we can model the way people reason – both with and without autism spectrum disorder. This can help us better understand both the autistic and non-autistic mind. And it gives you a good argument against that arrogant logic of Aristotle!
But there’s more! There are many different logics out there, and those are all suitable for different situations. Quantum logic incorporates theories from quantum mechanics, and there are all kinds of logics bearing connections to mathematics or philosophy. All these logics can help us to better understand the real world around us.
Wow! Did I just boggle your mind with all these possibilities? Or would you like to know more about logic or its connection to your favourite discipline? Leave me a comment and maybe you’ll see a new blog about it soon!