According to Arthur Koestler, who should know, there exists in the Grand Scheme of Things a hierarchy of truths. At the top there is mathematics and theoretical physics whose claims are easily corroborated and verified by mathematicians and physicists around the world, regardless of race, creed, or color. At the bottom (and here I interpolate) there are the headlines of the latest National Enquirer that scream at us from the checkout lanes of our local grocery store: “Hillary is a racist, bigot, and criminal!” We need to know how to differentiate among the types of claims — for they are all claims, some of them well-founded and others outrageous.

The sciences range downwards from physics to the biological sciences, geology, anthropology, the social sciences that rely on probability theory and therefore pass themselves off as exact sciences, to philosophy, history, and the like. Again, we need to know where we are on the hierarchy because each of these disciplines requires a different approach and different types of corroboration. History, for example, relies on first-hand testimony, written documents and independent corroboration from different sources, all regarded as reliable. The key is “corroboration.” The sciences and social sciences, even philosophy, require independent corroboration by others in the field to check on the accuracy of the claims being made. Did Caesar cross the Rubicon? Who says? What evidence is there to corroborate this claim? Thus the historian proceeds to provide us with an accurate picture of what has occurred in the past. The expert seeks to show that the claim is false. If it cannot be shown to be false after thorough study, we can accept it as true. Then he asks his fellow experts to duplicate his efforts and test the claim for himself or herself.

When the National Enquirer makes its outrageous claims we should (but seldom do) ask the same sorts of question: how can those claims be corroborated? Who makes the claims? Are those sources reliable? Can they even be tested? If so, how? These are the types of questions the lawyer asks in a trial when a person is facing possible felony charges and perhaps time in prison. We should all be so circumspect, equally suspicious and demanding of the truth and not satisfied with what are merely empty claims or accusations.

This is the job of critical thinking and it should be taught in all our schools and certainly in all our colleges and universities. We all tend to accept as true those claims that fit in nicely with our closely held beliefs, our belief-set as I call it. But the critical thinker will allow the possibility that a claim that does not fit in nicely with his belief-set might still be true. Those who lack critical thinking skills (whose numbers grow daily from the look of things) will believe whatever they are told on Fox News or read in the Enquirer. The problem is that those who believe whatever they hear or read without subjecting those claims to the tests of corroboration and verification are most likely to be lead astray by someone who, say, might want to steal their vote in an upcoming election, or sell them farmland in the Everglades. They fail to realize that something is not true simply because they want it to be true (it fits in nicely with their belief-set) or because the guy up there with the funny hair and the small hands says it is true. The fact that he said the opposite yesterday is lost on these people because they lack the critical filters that would weed out the falsehoods and lies and recognize the inconsistencies.

Critical thinking teaches us to have a healthy suspicion. Not that we will doubt all claims, but that we will suspect that those that seem outrageous might well be so. We will accept as true only those clams that can be corroborated and verified, like the scientist. We will also recognize among those claims that are scientific but outside our small field of knowledge that claims made by experts in the field, say scientists who have studied such things as climate change or the evolution for species over the millennia, are making claims that we ought to accept as true until or unless they are later shown to be false. We ought not to simply reject those claims because they don’t fit into our belief-set or because they make us feel uncomfortable.

In the long run, it pays to be critical and suspect that many, if not all, claims that are designed to sell us something (or someone) are probably not true, or at least that they demand further investigation and thought. They should not be accepted simply because we read them in our favorite newspaper or heard them on the News. That suspicion is healthy and it is what critical thinking is all about: making sure that we will not be mislead into accepting as true what is blatantly false — or electing a fool as our president.