Our species, Homo sapiens, is the first and, so far, still the only species to possess the capability to think rationally. All of the amazing progress that we enjoy could not have happened without rational thought. Obviously, our unique ability is extremely important.

Can you define precisely what is and what is not rational thinking? Do you think rationally?

Just because we have an ability does not mean that we always — or even usually — use it. We have the ability to run, but most of us do not run very often. Running is kind of hard work, so we do it only when it's important. However, some small fraction of us seems to enjoy running; they do it voluntarily. Rational thinking also is hard work, so many people do as little of it as they possibly can. Fortunately, like runners, some people seem to enjoy rational thinking. Also as with runners, there is a wide range of rational thinking abilities and it takes steady practice to be really good at it.

A relatively small cadre of rational thinkers can make contributions that lift and benefit all of society. That surely has happened. However, we are finding out that a small cadre of rational-thinking practitioners focused on the scientific disciplines is not sufficient to maintain and advance a free and prosperous society. We are in very serious trouble in that regard.

In the early chapters, rational thinking and rational self-interest are carefully defined. The high points in the progress of rational thought from its beginning to the present are summarized. We pause in the present to evaluate our condition before proceeding to project the most probable future. It's Homo sapiens from our very beginning to our eventual end.