As I’m teaching a course on critical thinking, I thought it would be useful to study the history of the concept. What have leading thinkers of the past conceived to be “critical thinking” and how have their perceptions changed over time?
One of the earliest — and most interesting –references that I’ve found is a sermon called the Kalama Sutta preached by the Buddha some five centuries before Christ. Often known as the “charter of free inquiry”, it lays out general tenets for discerning what is true.
Many religions hold that truth is revealed through scriptures or through institutions that are authorized to interpret scriptures. By contrast, Buddhism generally asserts that we have to ascertain truth for ourselves. So, how do we do that?
That was essentially the question that the Kalama people asked the Buddha when he passed through their village of Kesaputta. The Buddha’s sermon emphasizes the need to question statements asserted to be true. Further, the Buddha goes on to list multiple sources of error and cautions us to carefully examine assertions from those sources. According to Wikipedia, the Buddha identified the following sources of error:
Further, “Do not accept any doctrine from reverence, but first try it as gold is tried by fire.” The requires examination, reflection, and questioning and only that which is “conducive to the good” should be accepted as truth.
As Thanissaro Bhikkhu summarizes it, “any view or belief must be tested by the results it yields when put into practice; and — to guard against the possibility of any bias or limitations in one’s understanding of those results — they must further be checked against the experience of people who are wise.”
So how do the Buddhist commentaries compare to other philosophers? In the century after Buddha, Socrates is quoted as saying, “I know you won’t believe me, but the highest form of Human Excellence is to question oneself and others.” Almost 2,000 years later, Francis Bacon wrote, “Critical thinking is a desire to seek, patience to doubt, fondness to meditate, slowness to assert, readiness to consider, carefulness to dispose and set in order; and hatred for every kind of imposture.” A few hundred years later, Descartes wrote, “If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.” A hundred years after that, Voltaire wrote about the consequences of a failure of critical thinking, “Anyone who has the power to make you believe absurdities has the power to make you commit injustices.”
As the Swedes would say, there seems to be a “bright red thread” that ties all of these together. Go slowly. Ask questions. Be patient. Doubt your sources. Consider your own experience. Judge the evidence thoughtfully. For well over 2,000 years our philosophers — both Eastern and Western — have been saying essentially the same thing. It seems that we know what to do. Now all we have to do is to do it.