As a society, we need to agree on the scientific evidence on the different issues that we should be able to solve. Different ideologies or views can propose different solutions. What we should not accept is to continue living in parallel worlds, each with its own "reality". 

This attitude, moreover, can help us coexist better as a culturally diverse society, without thinking that these other views threaten our "reality". Neither we nor anyone else should have to choose between protecting their identity and accepting what is known about different topics. This is key. Dismantling this false dichotomy is not easy, as we have seen. Nor does there seem to be agreement yet on how it can be achieved. But identifying this as a goal can only help to achieve it. 

Throughout this book, we have emphasized that, in order to combat post-truth, part of what we need to do is understand how we know what we know, and for that it is essential to understand at least the basics of how science allows us to generate and validate evidence. One of the stumbling blocks we find in society to accomplish this is that science is often seen as a body of definite knowledge rather than what it primarily is: a set of tools that allow us to answer questions regarding factual issues. But, on the other hand, it is also true that, in order to combat post-truth, we will need not only empirical science, but also scientific approaches to the humanities, which will allow us to identify relevant problems and understand what difficulties there may be along the way and how we can achieve social cohesion in pursuit of the common good. 

We are a single human tribe, and we all live together in this complex world. But in order to see ourselves as one big family we will need, to begin with, to build bridges between the sciences and the humanities, or rather, between the human communities of professionals specialized in those areas. 

We need the "two cultures" of the sciences and the humanities to communicate better¹See Snow, C. P. (1959). The Two Cultures and the Scientific Revolution, Oxford, Oxford University Press. Available online. so that they can understand each other and provide complementary insights. This can be stimulated in several ways. In addition to recognizing the value and relevance of these two great areas of knowledge, and that there are competent experts in the sciences or in the humanities, we will need to work on building bridges and communication between the two. Thus a third axis appears in which one can be an expert: neither in one area nor in the other, but in building bridges between the two subcultures. Identifying the common good and the way forward is probably a philosophical task, but identifying goals and metrics in order to know whether or not we are moving in that direction will come from science. We cannot fix what cannot be measured. As Carl Sagan said, “Science is much more than a body of knowledge. It is a way of thinking... We need wide appreciation of this kind of thinking. It works. It's an essential tool for a democracy in an age of change.”

Knowing is better than not knowing, and it allows us to change and improve. A quality intellectual discourse will need to stand on both pillars, or it will collapse.

We also discussed in section 2 of this book that, in order to combat post-truth, we will have to be more alert in order to identify several factors that can hinder the recognition of the truth, such as irrational beliefs, emotions, cognitive biases and other flaws in our thinking, tribalism, difficulty in recognizing experts or in obtaining and assessing quality, undistorted information. One of the best tools we have for this purpose is to exercise introspection, understand what motivates us, what previous positions we hold, etc. Similarly, we need to try to understand others better, we need to listen to each other. And in order to do this, we need to train ourselves in empathy. We are all in this together, facing a common enemy: post-truth. Let's solve this all collaboratively, in a win-win game, a non-zero-sum game. 

It is always emphasized that we need more and quality education, although it is seldom explicitly stated what we mean when we say "more" and "quality". In view of the above, there are perhaps three areas to focus on in the education of new citizens. There is not yet much specific evidence in this regard, but at least they seem to be worth exploring further. 

Firstly, we need to improve scientific literacy, emphasizing the process of science, not just the product of science. Shouldn't we learn in school what evidence is or how to identify a scientific consensus? Within that literacy, we would also need to improve data literacy: how to look for data, how to read, weigh and understand what it says and, above all, what it does not. We should also understand that we can be wrong in our thinking, reason fallaciously or be subject to cognitive biases. It is important to understand uncertainty. When science is taught, messages usually emphasize that it does not give absolutely certain answers, but sometimes they forget to mention that its answers are as "absolute" as possible, so that today it is not valid to doubt, for example, that the Earth is round. Not every idea deserves to be taken seriously. 

Denialism and cultural relativism, which can be simplified as the position that "there are no facts, only interpretations," are threats to which we need to be alert, which we must try to identify in ourselves and in others, and which hide at their hard core the profoundly arrogant idea that our subjective experience is better at describing the world than the collective approaches we have developed as a human family throughout our shared history. 

Being scientifically literate also implies the conviction that science can describe the world around us with more certainty than our intuition. Moreover, it involves developing critical thinking, through which we can see how the evidence that is and is not there allows us to take positions, understand the complexity of phenomena, and make decisions. It is scientific literacy that tells us why we need to turn to competent experts when we are not, and how to distinguish a good expert from a false expert. It is also central to distinguish an authoritative argument, which is only based on the supposed authority of the person, from what we are told by an expert who is taking into account what is known in their field to support their position. 

One more clarification regarding science education. Being more educated does not in itself guarantee better thinking, for example. Educated people also are prone to cognitive biases, and it has been noted that sometimes that education only gives them more tools to protect their erroneous positions. Benjamin Franklin said: "So convenient a thing it is to be a reasonable creature since it enables one to find or make a reason for everything one has a mind to do." The most educated people also have the most extreme and polarized positions on scientific issues that "stir up" post-truth.²See Drummond, C. and Fischhoff, B. (2017). Individuals with greater science literacy and education have more polarized beliefs on controversial science topics, Proceedings of the National Academy of Sciences of the United States of America, 114(36): 9587-9592. It is not true that more education automatically implies more rational thinking. And if, despite the evidence, we continue to hold that view because we find the alternative counter-intuitive and uncomfortable, are we thinking rationally? 

What we are suggesting is not that educating ourselves in science will make us magically immune to the most frequent mistakes, but that it will make us more aware that these mistakes exist, and that they exist in all of us. And, if we believe we are safe from them, it is most likely that we are not identifying them, and not that they do not exist in us. 

Secondly, we need better information and media literacy. If we know how the information that we get can be intentionally or unintentionally distorted, at each and every stage from the generation of knowledge to our receiving it, we will be better prepared to combat post-truth. Sometimes, we will learn what we want to learn, and that may be biased by our own or others' motivations. Other times, we will learn what others want us to learn. An attitude of healthy skepticism will be essential to act with caution and not fall into the extremes, which are simpler and more attractive, but do not serve us well: that of absolute trust and that of absolute distrust in the information we get. This will also help us distinguish fake news from real news. 

We need to know that current incentives encourage the media to disseminate content in a tone that triggers emotional responses in us (surprise, outrage, amusement). We need to understand that a celebrity may believe in good faith that he was cured of cancer because he drank grass juice, and we also need to understand that if a media outlet unquestioningly interviews that celebrity, it propagates post-truth, and that misinforming audiences in that way poses a great threat to public health. But it does so not necessarily out of "malice", but because we consume such news. Even media outlets that struggle to provide correct, careful and excellent information are pressured by the need for acceptance by us, the consumers of their product. As long as we consume "junk" news, they will continue to generate it. Moreover, everything will remain the same as long as we continue to think of ourselves as consumers of news instead of agents who internalize, value and reward or punish the media by giving or taking away our attention and trust. Rewarding the scoop rather than in-depth analysis also leads to the dissemination of news without taking into account whether that knowledge is firm and reliable, whether it goes for or against the consensus, or whether it is relevant as news. It is important to be aware of this type of tension, and it is something that can be taught and learned. 

Finally, we need emotional, empathic and introspective literacy. This could give us tools to identify our own irrational beliefs and those of others, and to find out when we behave in a tribal manner. None of the above is going to work if we cannot accept that our motivations drive everything from what information we accept to how we process it, if we cannot understand that we are all different and believe different things. We need to hold on to a set of facts, accepted and shared by all, and understand that, from that starting point, we can still arrive at different conclusions based on our values or ideology. 

Much of what we strongly believe has a factual basis that can be known. But we usually don't take the trouble to find out what is known and what is not because it is more important to us that it fits our ideology or our vision of how the world should be. As argued in the book Factfulness, by Hans Rosling and collaborators,³Their children, Ola and Anna. "Facts don't come naturally. Drama and opinions do. Factual knowledge has to be learned."⁴https://www.gapminder.org/about-gapminder/. Hans Rosling was a great communicator who focused on finding novel ways to convey factual knowledge in a clear and engaging way. 

We can learn facts, but if we don't unlock our emotions around that learning, it is difficult for meaningful change to occur. We don't get out of this trap with scientific literacy or information and media literacy alone. We need to add introspection and empathy, which can also be learned, taught, fostered and trained. 

This emotional literacy can help us see how valuable it is to expose ideas so that they can be challenged and tested, and to understand that if our ideas are destroyed, we are not. It can also allow us to accept that it's not a matter of "I'm right, you're wrong". It is not that we reason properly and the others have to change. Sometimes it is the case, sometimes it won't be. We really need to accept that we might be wrong. 

In addition to introspection and empathy, in emotional literacy we include stimulating curiosity, the desire to know and to be surprised by the world, the favorable disposition to the new. As we saw,⁵We discuss curiosity in Chapter VII. this apparently helps to decrease tribalism, to have less polarized positions, it is a kind of vaccine against motivated reasoning. Curiosity can help us see that what contradicts our position does not necessarily threaten us, but that there is a challenge to be solved, that we can try to solve it well and that others can help us achieve this. Curiosity helps us  prioritize getting the right answer, rather than an answer that we like or is popular with our peers. 

Perhaps most importantly, emphasizing the emotional aspect could help us make this whole fight against post-truth matter to us. Because if it doesn't seem important to us, or if we are already resigned to the fact that nothing will get better, there will be no way to win. 

None of this is simple. Education is not usually viewed in this way and, in contexts where it is not yet possible to fully guarantee that a student will complete their compulsory education with the basic skills of reading comprehension and writing, this view may seem naïve, to say the least. Even so, we must never lose sight of the fact that if we choose not to change anything, we are doing exactly that. This means that the previously innocent option can now be seen as a specific and hopeful proposal, and that, from the design phase, it can be developed or discarded based on its assessed efficiency. 

But there are still more problems. If we were to include this approach in the educational curriculum, hopefully we would educate the children. But how do we reach adults? We are much more inaccessible, and we don't accept learning unless we are motivated, so somehow we would first need to break that barrier. 

Not everyone will join this fight against post-truth. Some will not be able to devote resources to it, in terms of time or attention. Others will not want to participate because they will prioritize other things, or will not find it relevant. Most of us are motivated by our pursuit of happiness; to have a decent life, to be healthy ourselves and for our loved ones to be healthy. We want to enjoy life and laugh. Who doesn't? What we are talking about requires effort, it is difficult, and seldom fun, but it is genuine and urgent. We are facing a problem that seems to be growing. If we don't manage to fight it now, who knows if we will be able to solve it later? Can we afford to wait? 

Perhaps, even if not everyone joins in, some of us can start. Vaccines that prevent communicable infections are special: when many people are vaccinated, not only do they protect themselves, but herd immunity is achieved, whereby, since pathogens cannot pass through the vaccinated, their circulation is prevented and thus the unvaccinated are also protected. Similarly, some of us can begin to fight post-truth. Perhaps when there are more of us, we will generate herd immunity. We could function as a decentralized, diverse and continuously improving immune system that fights post-truth. 

Yes, it is tiring to be busy, it takes effort and we will not always be up to the task. So let's pick our battles. Let's identify what seems most relevant to us and where our expertise can make the most difference. Trying to catch all the balls is exhausting and ineffective. If we hesitate whether to continue or not, let's ask ourselves what the alternatives are. 

Let's face the fact that we are not just consumers of information. We are the medium through which information is spread, and we have a responsibility to determine what gets to other people. An old phrase comes to mind: "You're not caught in traffic. You are traffic." We are not trapped in post-truth; we are post-truth. It's not just the outside that needs to be fixed. You also have to fix what's on the inside. 

As Cass Sunstein said, "habituation, confusion, distraction, self-interest, fear, rationalization, and a sense of personal powerlessness make terrible things possible." 

We need to develop and inhabit an attitude of healthy skepticism and let it become a permanent state. Skepticism as our only trait makes us distrust everything, see a "but" everywhere, and never take a chance on a new idea. On the other hand, a good predisposition to new, not very well founded ideas, but ideas that surprise us or seem interesting to us, can lead us to blind trust. Neither of these extremes works. We need to strike a happy medium. Healthy skepticism is that middle point between these two extremes, and this attitude can protect us from believing in bad ideas and failing to identify the good ones, as well as from believing in exaggerations that do not reflect reality, both those that make us very afraid and those that give us a lot of hope. "Curiously", these are the kinds of exaggerations that often make great news in the media or in social networks. 

When information comes to us, we have to question where and how it is coming from. We have to ask ourselves what information we are not getting. Let us act with healthy skepticism especially regarding statements that we agree with based on our emotions and biases, those that are intuitive to us. These are the most "dangerous" ones, they can deceive us if we do not pay attention. 

Healthy skepticism helps us focus on the processes behind the facts, and not only on the facts as the final product, and also, to do process-checking as well as fact-checking. 

With this view of healthy skepticism, we can challenge ourselves and others, fight to improve the quality of public discourse, and hold ourselves accountable for our contributions to post-truth, as well as point out and try to block those of others. To change the world, it is not essential to think big. Of course, the big decision-makers can join in, and their decisions will have great influence. But there is also much that can be done at the individual level. It's like the "fifty million people are wondering why a single plastic bottle could be polluting the planet" joke. 

Post-truth does not grow –at least not solely-- because there are "post-truth villains" pulling the strings behind the scenes. We are all responsible to a greater extent, through both action and inaction. Just as an effective strategy against school bullying is empowering peers who witness the aggression and do nothing by helping them to act, it is not enough to expose those who intentionally create post-truth. We also need to take responsibility for the situation. It's not just about being part of the problem or part of the solution. It is the risk of being part of the landscape, of turning from agents to mere walls that selectively echo our own prejudices. 

We are one big human family. Caring for it is a collaborative non-zero-sum game, and post-truth sabotages it, making us forget that in this world we exist with others, not in spite of them.

The struggle against post-truth is a struggle to protect human bonds, to inhabit a shared reality, even if our different ideological positions drive us apart. This way, at least, that divergence will emerge on the basis of facts accepted by all as real, and we will always be able to reconsider our positions. This common ground has an enormous advantage: there are big problems that we will have to solve together and that can only be solved if we choose to acknowledge them, attach importance to them and address them. Therefore, it is a non-zero-sum game: there is not one winner and one loser, but we can all win, or we can all lose. Let's try to win. 

We are in these post-truth times together and we will overcome post-truth together. With constant vigilance and healthy skepticism, taking care of ourselves and each other and being demanding, we can find the truth, highlight it, protect it. 

Fighting is not easy, but the alternatives are not only catastrophic, but also sad. They imply natural dangers to our survival, and, in addition, the real possibility of living isolated lives, impervious to others, of settling for weak debate and weak bonds. 

It will be, then, a fight of love and fear, fueled not only by what we stand to lose, but by what we can recover: the human connection that post-truth took away from us. The time has come to show agency, it is our opportunity to shout that we will not surrender meekly. That we care, and that we are not going to give up.