understanding inductive reasoning

​Human beings tend to find comfort in certainty, which is what drives us to draw conclusions and make predictions about the future. But our conclusions are often incorrect and our predictions often wrong, so how can science help us make them better? 

Well, it has to do with inductive and deductive reasoning. This post (and this week's video) will talk all about inductive reasoning, and I'll talk about deductive reason in another post soon. 

What is Inductive Reasoning?

​Inductive reasoning is a thinking process that involves taking a set of observations, recognising a pattern, then drawing conclusions. For example, if you had a bag full of coins, pulled out ten of them and found that they were all five cent pieces, you would conclude that all of the coins in the bag were five cent pieces. 

We do this all the time: drawing conclusions from our observations. And this thinking process (aka inductive reasoning) is an important part of the scientific process. It's what forms hypotheses and encourages experimentation (aka deductive reasoning). But, it's important to note that inductive reasoning are just general conclusions and not necessarily facts. 

Why can Inductive Reasoning go Wrong?

There are many ways our inductive reasoning can be incorrect. 

• If you're making a generalization based on a small set of observations (or as a scientist would put it, if you have a small sample size).
• There could be some variable that you hadn’t considered that’s influencing your results. 
• If your observations aren’t typical for the things that you’re observing. (This is what scientists call sampling bias.)
• If our biases are affecting our observations or our logic. 

As you can see, we shouldn't completely rely on inductive reasoning for drawing conclusions. In fact, to truly understand whether our conclusions are sound, we have to conduct experiments. 

A Personal Example of When My Own Inductive Reasoning Failed Me

About ten years ago, I took a trip to Sydney. It was a quick flight from Melbourne (where I was living at the time), so I only went for the weekend. But a weekend was long enough for me to go out to two restaurants which served pretty mediocre food and offered unfriendly service. So, I came to the conclusion that restaurants in Sydney weren't as good as in Melbourne.

Where did my inductive reasoning go wrong?

• Small sample size: I only had a sample size of two, which is not nearly large enough in a city of almost 20,000 restaurants.
• There may have been variables that I hadn’t considered, like maybe the chef had to call in sick that day, or maybe the server didn’t sleep well.
  
• The two restaurants I visited were right in the touristy area of the city, so not really a representative sample.
• Personal bias: You might not know this, but there’s a bit of a rivalry between Melbourne and Sydney, so I’m predisposed to think that everything from Sydney stinks. And I have to admit, that bias might have coloured my impression of the restaurants. ​

Admittedly, I started with an incomplete set of observations, then let my biases influence my logic to reach an incorrect conclusion. When really the fair thing to do would have been to withhold judgement until I had more data.

Why is  Poor Inductive Reasoning a Problem?

Well, inductive reasoning may not be a big problem if we’re just talking about my opinion of restaurants in Sydney; but rushing to conclusions CAN be a big problem when more important things are concerned.

This kind of poor reasoning could lead to everything from bad investments to stereotyping a group of people, or making the wrong decision for your health.

Now, unfortunately no matter how hard we try, we can never gain 100% certainty with inductive reasoning, but if we avoid bad logic and understand what makes a good set of data, we can make better conclusions and predictions. And if you ever travel to Sydney maybe you can avoid my mistake of being too quick to pass judgement. Even though Sydney stinks. Melbourne rulez.
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Putting it all Together

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In order to practice identifying flaws in inductive reasoning, check out my video on the topic below. Additionally, you can follow along with my accompanying worksheet, which you can purchase here. 

​Tell me: What are some conclusions or predictions that you know about that were shown to be incorrect? I’d love to hear about them in the comments below.