ducators, humanists and skeptics often question themselves: why is it difficult for people to change their minds, even when they hold beliefs that are clearly false, dangerous to them or to others, or ethically indefensible? While there are many, and complementary, answers for this question, we assume that one cause, at least for the difficulty that people have in changing some ideas, is that human beings hold their beliefs as an important part of themselves. As A. C. Grayling1 wrote, “those who never retract an opinion love themselves more than truth.” We would add: those who never consider changing an opinion may fear they can get hurt if something which they deeply believe turns to be false. Their world might turn upside down.

Spanish philosopher Fernando Savater wrote about how hard it is for people to have their beliefs questioned, and why this is a problem educators should face. According to Savater,2 any kind of education that aspires to be called humanist must encourage students to think, to argue, to reflect upon claims and criticize them (when there are good reasons to do it), and to justify their beliefs. If a teacher assumes that people’s ideas are like sacred cows that must be untouched and unquestioned, it is unlikely – if not impossible – that the students will enjoy an atmosphere of intellectual freedom and be provided with the necessary stimulus to practice their critical thinking skills.

While there is no magic solution for the “desacralization of ideas” in a classroom, we discuss three concepts that, when applied at schools, may help students feel more comfortable in expressing their ideas, and in having these ideas being confronted by classmates. In addition, these concepts may help educators feel more confident in proposing discussions and promoting critical thinking in their classes.

The first concept is the idea of fallibilism. We are aware that fallibilism may be understood in different ways, so we adopt a kind of constructive fallibilism: many of our beliefs may turn out to be mistaken, so we must be prepared to accept that we might be wrong about several things – even things that we hold dear – and also be open to change our ideas if sufficient reasons and evidence demand so. At the same time, the fallibilism we endorse here admits that it is possible for us to know things, at least provisionally.

Accepting fallibilism is not the same as being an extreme skeptic, living in a state of permanent doubt about everything, or thinking that it is not possible to have any knowledge about the world. We need to make decisions, we need to think about many issues daily, and so it is essential that we make an honest effort to find the best information about things in order to take the best course of action available to us. We cannot function in the world if we are extreme skeptics; our daily needs imply that we must value the search of reliable knowledge. However, without forgetting that we might be wrong.

It is also important to emphasize that fallibilism does not entail relativism. Relativism, especially in its most extreme forms, also hampers meaningful discussions. If a relativist educator thinks all opinions are equally valid, what is the point in fostering discussions in class? Perhaps the acceptance of relativism is one of the most difficult obstacles for the desacralization of opinions, because, as philosopher Michael Lynch3 points out, relativism seems to encourage greater toleration, an opportunity for every person to have his or her ideas accepted as truth. But Lynch is correct when he stresses that it is dogmatism, not the belief in truths, that is enemy of tolerance. That is, not understanding that you may be mistaken prevents you to look for information that can disconfirm what you think is true. Dogmatism may also make you hostile towards people who think differently from you, and resistant to the possibility of changing your mind.

There is another very important aspect related to fallibilism. We humans are prone to commit mistakes. To err is a natural component of being human. Mistakes are not intrinsically bad because they give us the possibility to improve our knowledge of many questions. If we capitalize on our own mistakes, we may enjoy a better understanding of things and gain information that is more reliable and may help guide us in whatever we do. We may also have a better apprehension of the things of the world.

The openness to the possibility of being mistaken that we advocate here is compatible with the attitude defended by the scientific skepticism movement, or the new skepticism. Paul Kurtz4 wrote that the new skepticism is vital not only for the sciences, but also for the ordinary life of people. The new skeptics assume that it is possible for us to have reliable knowledge and, at the same time, embrace that certainty is a matter of degrees. This means that knowledge may be subject to revision, and thus is not absolute. So, if we want to know things better, we must work hard.

Given that we might be wrong in what we believe, it is important to continuously search for the best reasons and the most reliable evidence regarding a certain claim, and eventually reconsider our beliefs if the result of our inquiry shows we are mistaken. It is necessary to embrace the critical spirit, the second concept that underlies the desacralization of ideas. Critical spirit is an expression put forward by philosopher Harvey Siegel as an indispensable element of critical thinking. According to Siegel,5 a person who is imbued of the critical spirit has a respect for reasons, “an inclination to seek reasons and take them seriously as guides to belief and action,” as well as “an appreciation of objectivity, impartiality, and honesty in the consideration of evidence and argument; and a general commitment to the ideal of rationality as a guide to life.” The critical spirit, in sum, helps people to actively search for the best reasons and evidence regarding any claim. It is necessary, as Siegel also highlights, to have the ability to assess the claims adequately, but having the disposition to do so is the first, and essential, step.

So far, we have postulated that it is important to foster the idea that we may have beliefs that are mistaken and, because of that, it is necessary to adopt an attitude of constantly seeking reasons and evidence to calibrate our ideas according to how reasonable they are. For these ideas to influence the habits of the students (and educators) in a classroom, we suggest that the school environment must help students feel comfortable in putting their ideas to debate. However, the idea of having their ideas debated, or of being criticized by their peers may be unsettling for many students. Therefore, it is time to present our third concept: Daniel Dennett’s advice about how to gently criticize ideas.

Dennett6 presents the “Rapoport rules” (after the psychologist Anatol Rapoport, who formulated them) as a list of recommendations for debaters not to be too harsh when criticizing their opponents’ ideas, even when there are clear contradictions in their discourse. According to the Rapoport rules, to compose a successful (and gentle) critical commentary one must (1) “attempt to re-express your target’s position so clearly, vividly, and fairly that your target says, ‘Thanks, I wish I’d thought of putting it that way’”; (2) emphasize any points of agreement with her opponent, “especially if they are not matters of general or widespread agreement”; (3) mention what she has learned from her opponent’s ideas; and (4) finally criticize the idea, expressing her disagreements.

Rapoport rules emphasize the criticism of ideas, not people, and this depersonalization may help students feel not personally offended when one of their ideas is under scrutiny. It also helps in showing students how important it is to listen to ideas properly and to try hard to understand them without making any straw man. As Savater7 wrote, it is people who must be respected, not their ideas, and the right to express our own opinions implies that our ideas may be heard and discussed, not unquestionably accepted. Having your ideas discussed, in turn, means that people are interested in what you are telling them, and they think your claims need to be taken seriously. This is truly a sign of intellectual respect.

A final piece of advice specifically concerns educators. Many authors who have written about critical thinking in education stress the importance of teachers as role models for critical thinking. So, if teachers want their students to be critical thinkers, it is important that the educators themselves are critical thinkers. That implies being open to review his or her ideas, accepting claims on the basis of reasons and evidence, and not authority, and being moved by the critical spirit to evaluate fairly the ideas of students and his or her own beliefs. It also implies cultivating an environment that fosters meaningful discussions with the students, and in which their ideas are taken into account to a point where they are worthy of discussion.

There are limits to the effects of the ideas we presented here, of course. Some people believe things dogmatically, that is, they really do not want to have them criticized, and do not comprehend that they can be wrong. So, searching for better evidence does not make sense for them. Additionally, we are also prey of many cognitive biases, most of all we do not even recognize. Nevertheless, a difficulty is not an impossibility. Neuroscientist Robert Burton8 writes that we can consciously input information that is contrary to our beliefs, and then modify our preexisting set of ideas about virtually anything. Perhaps, understanding that we need to know more about a certain claim to have a more reliable basis to believe it, and daring to investigate it may help us create a habit to do so more constantly, and to extend it to other questions.

In The Expanding Circle, Peter Singer argues in favor of the role of reason in ethical thinking and in moral progress, and one of his metaphors also applies to what we have been discussing here.9 “Beginning to reason is like stepping onto an escalator that leads upward and out of sight,” writes Singer. “Once we take the first step, the distance to be travelled is independent of our will and we cannot know in advance where we shall end.” The same, we conclude, may happen to those who dare to start reasoning about the things they think they know for sure.