Logic and Intuition

Logic is the set of rules and principles we use to determine whether a conclusion correctly follows from the information or assumptions of an argument. (An argument, in this context, is essentially the claim that’s being made, including how that claim is backed up.)

Intuition, in contrast, is the immediate sense that something is true or accurate without consciously thinking through reasons or evidence.
Another way to think about this is:

Broadly speaking, intuition and logic can both serve useful purposes, depending on the situation. For instance, intuition is useful when we have to make low-stakes decisions around personal preference (e.g. choosing what to eat for breakfast).

However, when it comes to assessing information and determining truth, intuition is unreliable, prone to error, and often actively harmful.

Below, we’ll go over some areas where intuition fails us, and why that is.

Probability and statistical thinking

We didn’t evolve to be able to grasp extremely large numbers, randomness, and chance. As a result, our intuition about these concepts is very inaccurate. In fact, there is a whole list of just statistical errors we tend to make. These include:

• Overestimating the likelihood of rare but dramatic events (like plane crashes)
• Underestimating the role of randomness (like when we’re gambling)
• Misunderstanding base rates (like in medical diagnoses)

Correlation and Causation

A correlation-causation error is when we incorrectly assume that because there is a correlation between two things, one must be causing the other. We evolved to seek out patterns, and we intuitively assume connections that often aren’t really there. This works well for surviving in the wild, but not so much for navigating a complex civilization.

Correlation-causation errors can lead us to falsely believe things like:

• Video games cause violent crime
• Vaccines cause autism
• Presidential administrations cause gas prices to rise or fall

Large-scale systems and abstract data

We evolved to deal with small groups and visible, quick cause-and-effect relationships. Our intuition falls apart when dealing with large and complex systems, especially when those systems have delayed feedback (meaning there’s a large gap in time between an action and its consequences). This leads us to struggle to understand things like:

• Economic models
• Pandemics
• Climate and ecological systems

Confirmation and disconfirmation of beliefs

As we discussed in the previous chapter, our cognitive bias leads our intuition to focus on things that confirm our existing beliefs and ignore things that don’t. This leads to:

• Believing a stereotype is true because we’ve “seen it happen” — even though there were likely many more examples where it didn’t happen that we ignored
• Needing only a few confirming anecdotes to increase our confidence in a pre-existing belief, whereas we need many more disconfirming anecdotes to weaken that same belief

Assessing our own competence and knowledge

Consistent with our poor intuition for statistics and large numbers, we also tend to have poor intuition when it comes to our own competence and knowledge. We tend to:

• Overestimate our knowledge and understanding of a topic
• Rate ourselves as better-than-average in most domains, even when we’re not

emotion and identity

At our core, we’re very emotional creatures who highly value our sense of identity (sometimes sacrificing our lives for it). As a result, our intuition is at its worst when the information we’re being asked to assess:

• Connects with our sense of identity
• Heightens our emotions

To be clear, we’re not arguing that everyone should be emotionless robots. Emotions are fundamental to our human relationships and our human experience. But when it comes to assessing the accuracy of information, emotions don’t serve us best.

For all the areas we just discussed where intuition fails, it’s important to understand that:

• You’ll still have an intuitive response
• That intuitive response will feel coherent and correct (although it usually isn’t)

When things feel right, that tends to demotivate us from learning more about the topic and checking if our feeling matches reality. This means that it’s very easy to end up thinking we have a better understanding of the world than we actually do.

Using logic helps us gain a more accurate view of the world by applying rules and techniques that circumvent our errors of intuition. It’s why logic is the backbone of the scientific method — without which we wouldn’t have anything from asphalt-paved roads to live-saving medicine to modern smart-phones.