The final chapter of the book is called “The Fourth Quadrant.” Sounds kind of mysterious, right? What is the fourth quadrant and why is it important?

In short, Johnson categorizes inventions into 4 quadrants and shows that a lot of them are happening in a way that supports his theory – the theory that networks are more and more important to the creation of new ideas.

Let me explain a little more. Johnson takes 200 of the most significant inventions/discoveries of the past few centuries and classifies them into one of four categories.

  • First, the invention/discovery either came from an individual or from a network.
  • Second, the idea was created for profit – i.e. to be marketed – or in a non-market, open-source, more academic type environment.
  • The combination of those variables creates four possible categorizations.

He looks at great inventions of the past: the printing press, portable watches, the microscope. He shows how some of these ideas came from individuals, some from networks, some were made to be sold, others made in a more open-source manner.

However, as you fast-forward in time, more ideas are classified as having come from networks without the inventors specifically trying to market the invention.

Things like computers, braille, vitamins, the MRI, global warming, GPS, and radar all fall into this fourth quadrant of being created from a network of people working outside of a specific commercial endeavor.

By the time Johnson is done classifying great ideas from history, the fourth quadrant is overflowing. This shouldn’t be surprising; if it didn’t work out this way, Johnson probably wouldn’t have written this book, right?

So…this exercise helps to demonstrate and reinforce Johnson’s theory: a lot of good ideas come about from people working together in networks, and you don’t necessarily need a market incentive for an idea to develop.

More on the fourth quadrant in another post next.