“…There is a traditional optimistic story that runs as follows. Our hero is a prisoner who has been sentenced to death by a tyrannical king, but gains a reprieve by promising to teach the king’s favorite horse to talk within a year. That night, a fellow prisoner asks what possessed him to make such a bargain. He replies, ‘A lot can happen in a year. The king might die. I might die. Or the horse might talk!’…”
by Professor David Deutsch FRS, University of Oxford
All evils are caused by insufficient knowledge.
Optimism is, in the first instance, a way of explaining failure, not prophesying success. It says that there is no fundamental barrier, no law of nature or supernatural decree, preventing progress. Whenever we try to improve things and fail, it is not because the spiteful (or unfathomably benevolent) gods are thwarting us or punishing us for trying, or because we have reached a limit on the capacity of reason to make improvements, or because it is best that we fail, but always because we did not know enough, in time. But optimism is also a stance towards the future, because nearly all failures, and nearly all successes, are yet to come. Optimism follows from the explicability of the physical world, as I explained in Chapter 3. If something is permitted by the laws of physics, then the only thing that can prevent it from being technologically possible is not knowing how. Optimism also assumes that none of the prohibitions imposed by the laws of physics are necessarily evils. So, for instance, the lack of the impossible knowledge of prophecy is not an insuperable obstacle to progress.
That means that in the long run t here are no insuperable evils, and in the short run the only insuperable evils are parochial ones. There can be no such thing as a disease for which it is impossible to discover a cure, other than certain types of brain damage—those that have dissipated the knowledge that constitutes the patient’s personality. For a sick person is a physical object, and the task of transforming this object into the same person in good health is one that no law of physics rules out. Hence there is a way of achieving such a transformation—that is to say, a cure. It is only a matter of knowing how. If we do not, for the moment, know how to eliminate a particular evil, or we know in theory but do not yet have enough time or resources (i.e. wealth), then, even so, it is universally true that either the laws of physics forbid eliminating it in a given time with the available resources or there is a way of eliminating it in the time and with those resources.
The same must hold, equally trivially, for the evil of death—that is to say, the deaths of human beings from disease or old age. This problem has a tremendous resonance in every culture—in its literature, its values, its objectives great and small. It also has an almost unmatched reputation for insolubility (except among believers in the supernatural): it is taken to be the epitome of an insuperable obstacle. But there is no rational basis for that reputation. It is absurdly parochial to read some deep significance into this particular failure, among so many, of the biosphere to support human life—or of medical science throughout the ages to cure ageing. The problem of ageing is one of the same general type as that of disease. Although it is a complex problem by present day standards, the complexity is finite and confined to a relatively narrow arena whose basic principles are already fairly well understood. Meanwhile, knowledge in the relevant fields is increasing exponentially.
Sometimes ‘immortality’ (in this sense) is even regarded as undesirable. For instance, there are arguments from overpopulation; but those are examples of the Malthusian prophetic fallacy: what each additional surviving person would need to survive at present-day standards of living is easily calculated; what knowledge of the person would contribute to the solution of the resulting problems is unknowable. There are also arguments about the stultification of society caused by the entrenchment of old people in positions of power; but the traditions of criticism in our society are already well adapted to solving that sort of problem. Even today, it is common in Western countries for powerful politicians or business executives to be removed from the office while still in good health.
There is a traditional optimistic story that runs as follows. Our hero is a prisoner who has been sentenced to death by a tyrannical king, but gains a reprieve by promising to teach the king’s favorite horse to talk within a year. That night, a fellow prisoner asks what possessed him to make such a bargain. He replies, ‘A lot can happen in a year. The king might die. I might die. Or the horse might talk!’ the prisoner understands that, while his immediate problems have to do with prison bars and the king and his horse, ultimately the evil he faces is caused by insufficient knowledge. That makes him an optimist. He knows that, if progress is to be made, some of the opportunities and some of the discoveries will be inconceivable in advance. Progress cannot take place at all unless someone is open to, and prepares for, those inconceivable possibilities. The prisoner may or may not discover a way of teaching the horse to talk. But he may discover something else. He may persuade the king to repeal the law that he had broken; he may learn a convincing conjuring tick in which the horse would seem to talk; he may escape; he may think of an achievable task that would please the king even more than making the horse talk. The list is infinite. Even if every such possibility is unlikely, it takes only one of them to be realized for the whole problem to be solved. But if our prisoner is going to escape by creating a new idea, he cannot possibly know that idea today, and therefore he cannot let the assumption that it will never exist condition his planning.
Optimism implies all the other necessary conditions for knowledge to grow, and for knowledge-creating civilizations to last, and hence for the beginning of infinity. We have, as Popper put it, a duty to be optimistic—in general, and about civilization in particular. One can argue that saving civilization will be difficult. That does not mean that there is a low probability of solving the associated problems. When we say that a mathematical problem is hard to solve, we do not mean that it is unlikely to be solved. All sorts of factors determine whether mathematicians even address a problem, and with what effort. If an easy problem is not deemed to be interesting or useful, they might leave it unsolved indefinitely, while hard problems are solved all the time.
Usually the hardness of a problem is one of the very factors that cause it to be solved. Thus President John F. Kennedy said in 1962, in a celebrated example of an optimistic approach to the unknown, ‘We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because but because they are hard.’ Kennedy did not mean that the moon project, being hard, was unlikely to succeed. On the contrary, he believed that it would. What he meant by a hard task was one that depends on facing the unknown. And the intuitive fact to which he was appealing was that although such hardness is always negative factor when choosing among means to pursue an objective, when choosing the objective itself it can be a positive one, because we want to engage with projects that will involve creating new knowledge. And an optimist expects the creation of knowledge to constitute progress—including its unforeseeable consequences.
Thus Kennedy remarked that the moon project would require a vehicle ‘made of new metal alloys, some of which have not yet been invented, capable of standing heat and stresses several times more than have ever been experienced, fitted together with a precision better than the finest watch, carrying all the equipment needed for propulsion, guidance, control, communications, food and survival’. Those were the known problems, which would require as-yet-unknown knowledge. That this was ‘on an untried mission, to an unknown celestial body’ referred to the unknown problems that made the probabilities, and the outcomes, profoundly unknowable. Yet none of that prevented rational people from forming the expectation that the mission could succeed. This expectation was not a judgment of probability: until far into the project, no one could predict that, because it depended on solutions not yet discovered to problems not yet known. When people were being persuaded to work on the project—and to vote for it, and so on – they were being persuaded that our being confined to one planet was an evil, that exploring the universe was good, that the Earth’s gravitational field was not a barrier but merely a problem, and that overcoming it and all the other problems involved in the project was only a matter of knowing how, and the nature of the problems made that moment the right one to try to solve them. Probabilities and prophecies were not needed in that argument.
Pessimism has been endemic in almost every society throughout history. It has taken the form of t he precautionary principle, and of ‘who should rule?’ political philosophies and all sorts of other demands for prophecy, and of despair in the power of creativity, and of the misinterpretation of problems as insuperable barriers. Yet there have always been a few individuals who see obstacles as problems, and see problems as soluble. And so, very occasionally, there have been places and moments when there was, briefly, an end to pessimism. As far as I know, no historian has investigated the history of optimism, but my guess is that whenever it has emerged in a civilization there has been a mini-enlightenment: a tradition of criticism resulting in an efflorescence of many of the patterns of human progress with which we are familiar, such as art, literature, philosophy, science, technology and the institutions of an open society. The end of pessimism is potentially as beginning of infinity. Yet I also guess that in every case—with the single, tremendous exception (so far) of our own enlightenment—this process was soon brought to an end and the reign of pessimism was restored.