By Jorge Valdez
Those of us who work in science in general, and in the biomedical and health sciences in particular, share a fundamental paradigm: evidence generated through the scientific method is sufficient to establish something as true, or at least as reliable. This is how we were trained, and how, in turn, we train others.
Yet in recent years, we have observed—not only with surprise but with genuine astonishment and bewilderment—that those who hold political power often make decisions not merely without supporting evidence, but frequently and quite openly in direct opposition to it.
This gives rise to a fascinating paradox: even when data and information are readily available, the mind—or minds, since this can be a collective phenomenon—refuses to accept them or actively resists doing so. It becomes clear, then, that scientific evidence does not become “self-evident” simply by existing.
The great science communicator Carl Sagan understood well that evidence competes with emotional comfort: “It is far better to grasp the universe as it really is than to persist in delusion, however comforting that delusion may be.”
I will try to explain why evidence—scientific truth—is so often “unseen,” even when it is clear to scientists, and why it must overcome multiple psychological and social barriers before it can be integrated as shared truth.
Our brains are not objective processors; above all, they are pattern-seeking organs that look for confirmation of what they already believe. When data contradict our prior beliefs, our identity, or our values, the mind tends to ignore them, discredit the source, or focus on the lone exception that appears to reinforce the existing rule. This phenomenon is known as confirmation bias.
Moreover, when scientific evidence forces us to admit that we are wrong—or that, for example, our lifestyle is harmful—it generates a psychological discomfort known as cognitive dissonance. To relieve that discomfort, it is often easier to deny the evidence than to change one’s behavior or way of thinking.
Although he was a writer rather than a scientist, Leo Tolstoy captured this cognitive blockage with remarkable precision: “I know that most men, including those at ease with problems of great complexity, can seldom accept even the simplest and most obvious truth if it would oblige them to admit the falsity of conclusions they have proudly explained to others.”
Science is also frequently counterintuitive. A classic example suffices: for centuries it was maintained— and defended even by political and religious authorities— that the Sun revolved around the Earth. Intuition suggested it did: the Sun appears to move around us. Science demonstrated the opposite: it is the Earth that orbits the Sun at an extraordinary speed. Our “common sense” is designed for immediate survival, not for understanding complex systems such as climate change or quantum physics.
Evidence appeals to reason; acceptance of that evidence, however, appeals to identity. When science demands that we change who we are or admit that we have been wrong for decades, the mind often chooses, quite simply, “not to see.”
Henry David Thoreau explained this selective blindness with clarity: “A man receives only what he is ready to receive… The phenomenon or fact that cannot in any way be connected with the rest of what he has observed, he simply does not observe.”
In this sense, the history of science shows that evidence becomes socially accepted only after passing through three stages. The first is ridicule, when the new idea is deemed absurd. The second is fierce opposition, when it is perceived as a threat to the established order or to vested interests. Finally comes acceptance, when it becomes so obvious that it seems as though we had always known it— as happened with the recognition of handwashing as a key measure to prevent infections.
In an era defined by fake news and disinformation, scientific evidence competes with post-truth. Understanding it requires an active effort in media literacy and critical thinking. It is not enough for the data to exist; we must also have the mental readiness to see it.
Author
Jorge Valdez García is the head of the Research and Educational Innovation Unit in Health Sciences at the Institute for the Future of Education (IFE) of Tecnológico de Monterrey. He is a member of the National System of Researchers and the Mexican Academy of Surgery. He is the scientific editor of TecScience.
