A few major decisions determine a good portion of how our lives, careers, and relationships turn out. The outcomes of these decision points will reverberate for years.

Even small decisions can matter as they accumulate over the years.

• We’re not as rational as we think. 
• We’re not prepared. We don’t understand the invariant ideas — the mental models — of how the world really works. 
• We don’t gather the information we need. We make decisions based on our “guts” in complex domains that require serious work to gather all the needed data. 

We live in a society that demands specialization. Being the best means being an expert in something.  A byproduct of this niche focus is that it narrows the ways we think we can apply our knowledge without being called a fraud.

We should apply all the knowledge at our disposal to the problems and challenges we face every day.

• Inversion — Otherwise known as thinking something through in reverse or thinking “backwards,” inversion is a problem-solving technique.
• Second-Order Thinking — Ask yourself, “And then what?”
• The Map Is Not the Territory —The map of reality is not reality itself. If any map were to represent its actual territory with perfect fidelity, it would be the size of the territory itself.