Uncertainty in Scientific Explanations

One of the chief aims of science is understanding. The primary way that we achieve understanding of natural phenomena is by constructing explanations of how and why the phenomena occur as they do. The explanations provided by science are inherently uncertain. Due to the complexity of the phenomena being explained and our limitations as humans, scientists rely on models when constructing explanations. By their vary nature, models are uncertain because they essentially involve idealizations (abstractions or distortions of the facts) for the purpose of simplification. Although scientists legitimately infer that the best explanation of a given phenomenon is true, this method of inference is always uncertain for at least two reasons. The first is simply that the data being explained are limited (i.e., there is always more data that could have been gathered). The second is that there are always alternative explanations that might later be discovered.

Uncertainty Is Inherent in Science

At times people seem to have a mythical view of science as an infallible source of absolute certainty. Despite the prevalence of such a view, it is deeply misguided. All science is inherently uncertain. Two key factors that contribute to science’s inherent uncertainty are the complexity of natural phenomena and human limitations. Although the challenges posed by these two factors can be somewhat mitigated by way of scientific methods of investigation and the use of precise mathematical formulations, neither can be fully done away with. As a result, all science, no matter how precise or careful the methods it employs, is inherently uncertain. This is important to realize not only for truly understanding the nature of science, but also for appreciating that pointing out uncertainties that exist in domains like climate science, evolution, and vaccination in no way undercuts their claims to being legitimate, trustworthy science.

Uncertainties in Vaccination

Whereas vaccines have helped save millions of lives over the past several decades, today there is a significant anti-vaccination (anti-vaxx) movement, especially in the United States, that questions their safety. The problem is that these anti-vaxx arguments focus on rare cases of side effects or—even worse—on unfounded connections between the administration of vaccines and particular conditions such as autism. Such reactions make people overlook the fact that several diseases that in the past killed millions of people have been completely or almost completely eradicated thanks to vaccines. Even though vaccine side effects are a real possibility, one has to weigh the risk of facing those (which is very low and arise in relatively rare cases) against the hundreds or thousands of children who, thanks to the vaccine, will avoid hospitalization or even death. Uncertainties always exist, and we cannot be absolutely certain about the efficacy and safety of any vaccine. But for many of them, there is solid evidence that the problems are rare, and certainly the affected individuals are a lot fewer than those who might suffer and even die from the disease.

Uncertainty in Scientific Predictions

A primary good of science is that it allows us to accurately predict what will happen in the future. Knowing what to expect helps alleviate anxiety about the future and allows for good planning. However, although scientific predictions are often very precise and accurate, they are inherently uncertain. In order for a scientific prediction to be certain, several conditions would have to be satisfied. First, it would have to be certain that the universe is deterministic, but this is contested by both philosophers and scientists. Second, it would have to be certain that the actual scientific laws governing the deterministic universe have been identified—this is far from certain. Third, the precise initial conditions that the prediction is drawn from would have to be known with certainty—it is impossible to know these with certainty. Nevertheless, despite the fact that scientific predictions are uncertain, it would be foolish to disregard them.

Uncertainties in Forensic Science

There is a general impression, enhanced by many TV shows, that forensic analyses are objective and infallible. Yet this is far from true. There are many reasons for this. Forensic analyses are not only limited by the quality and the quantity of the DNA analyzed, but also by mistakes that can be made during the interpretation of the findings. There are many uncertainties inherent in the respective procedures, and these must be carefully considered before a conclusion is drawn. Whereas forensic DNA analyses can really be informative, they have to be judged against other types of evidence. Most importantly, all these have to be carefully considered before a juridical decision is made all while making efforts to limit biases that might interfere.

Uncertainties in Genetic Testing

Genetic tests are becoming increasingly affordable; however, the way they are marketed might make people think that they can provide more answers than they actually can. There are many uncertainties involved. Even if we are sure that a person carries a particular DNA variant and that this variant is implicated in a particular disease—which for many variants is not entirely clear—there is not much that we can do with this information until the underlying biological mechanism is understood. It is only after understanding what problem is caused by the particular variant that specific recommendations can be made. However, the way genetic tests are usually marketed is not explicit about these uncertainties. On the contrary, it is often promised that such tests reveal information that is actually impossible to obtain.

Understanding Versus Being Certain

Understanding, rather than certainty, is the true aim of science. This is something that scientists and philosophers agree upon for good reasons. There are two main reasons for this. The first reason is that understanding is particularly valuable. It is widely acknowledged that understanding is a cognitive achievement that is even more valuable than knowledge. So, when aiming at understanding, science aims at an intellectual good that is very valuable. The second reason is that, as the aim of science, focusing on understanding instead of certainty provides a solid account of the success of science. If certainty were the aim of science, then science has not been very successful since it never achieves certainty. However, science has continually achieved deeper understanding of natural phenomena, so if understanding is the aim, science has been tremendously successful.

Uncertainties in Climate Science

Whereas there is broad agreement among most climate scientists that climate change is occurring and that it is mostly due to human activities, many people doubt this. There are several reasons for this. One is that, despite the solid evidence for climate change, uncertainties remain about its exact pace and mechanisms. Scientists may debate these issues among themselves, and this debate might be perceived as a lack of consensus among them even though this is not at all the case. Furthermore, the public representation of this topic often fails to show that the vast majority of climate scientists agree that climate change is happening because of what we humans do. At the same time, uncertainties remain, and so the predictions of scientists have limitations. What is necessary is for scientists to clearly communicate the evidence and explain that uncertainties may blur the details but not the big picture.

In Science We Trust—Or Don’t We?

Scientists are experts in their respective domains because they have the knowledge, credentials, experience, and affirmation of their peers. They are, therefore, the experts when it comes to scientific matters. But individual scientists cannot know everything. Consequently, what matters is not the views of individual scientists but the collective and consensus view of the scientific community. However, the public is divided on the issue of whether to trust science and scientists. Polls in the United States show that scientists are relatively highly respected compared to other professionals, but, at the same time, about half of the people only have some trust in scientists. Worse than that, political orientation rather than science knowledge seems to have a major impact on attitudes toward science. Finally, even though there is a consensus view among scientists on topics like climate change, the public perception is that scientists are divided on such issues.

How Uncertainty Makes Science Advance

Rather than being a detriment to science, uncertainty actually helps it advance. And understanding the role that uncertainty plays in science is extremely helpful for avoiding four serious dangers. First, appreciating uncertainty in science helps one to avoid being dogmatically certain. Good science is always open to revision in the face of new evidence. Second, appreciating uncertainty in science allows one to avoid the mistaken view that all theories and ideas are equally plausible. Third, since uncertainty is an inherent feature of science, appreciating its role helps one better understand science. Fourth, with a proper appreciation of uncertainty in science, it is much harder for one to be deceived about things like the link between tobacco smoke and cancer or the reality of climate change. In the end, uncertainty in science helps us to make the best decisions we can while encouraging us to continually seek new discoveries.