Reasoning

The traps of Induction, Deduction, and Insight.

When we use our memories to deal adaptively with the present and the future, we are reasoning. A large part of what we call intelligence is our capacity to reason. We are able to reason in different ways. We can use analogies and induction, or we can use deduction and insight.

Analogies

In an earlier article, we saw that analogies are useful when it comes to understanding difficult issues and that practicing making them helps solve new problems we might face. Next to applying analogies, we can use inductive reasoning to reach conclusions.

Induction

We can use the experiences we’ve had and the observations we’ve made to draw general conclusions about something. We can even use other people’s experiences and observations that — together with our own — provide some evidence for a (seemingly) general truth. This method of reasoning is called inductive reasoning. The problem with this type of reasoning is that the conclusion you reach might not be true at all.

For instance, if you’ve had a bad experience with the IT helpdesk of your organization, and your closest colleague has had a similar bad experience, it would be easy for you to induce from both your experiences that the helpdesk really sucks. Little do you know that the same helpdesk provides adequate help to dozens of other colleagues every single day — you and your colleague just happened to be the odd ones out.

Inductive reasoning is particularly vulnerable to biases of all sorts.

Deduction

Rather than draw a conclusion that might be true, based on bits and pieces of information (induction), deduction tries to arrive at a logical conclusion after careful observation and assessment of premises. If the premises are true, then the conclusion must also be true — if the reasoning is done correctly.

If all birds have feathers, and sparrows are birds, then sparrows must have feathers. If the premises — all birds have feathers and sparrows are birds — are true, then the conclusion that sparrows must have feathers is also true. This sort of puzzle is called a syllogism.