Can the existence of an afterlife be proven? The scientists looking for God

Now that singer Rosalía has embraced mysticism and the “[Spanish protest movement] 15-M philosopher” Ernesto Castro has converted to Christianity, it is not surprising that science is being seduced by God as well. Scientists around the world are investigating topics such as heaven, reincarnation, and the immortality of the soul. The majority of the scientific community, however, remains skeptical and even questions whether the scientific method is suitable for addressing these issues.

This branch of scientists is thriving online and in bookstores. To conclude that a spirit, a heaven, or a deity exists, they point to observations of various phenomena. Some are as fundamental as the extraordinary leap from inert matter to living beings, which engineers Michel-Yves Bolloré and Olivier Bonnassies use to argue for the existence of a creative intelligence in their essay Dios. La ciencia. Las pruebas (God. The Science. The Evidence, Funambulista, 2023), which has sold more than 250,000 copies in France. Others are more anomalous or less studied, such as children who remember past lives or so-called near-death experiences (NDEs): intense episodes some people report after surviving a life-threatening event, like leaving one’s body, passing through a tunnel, or seeing a bright light.

Studying these phenomena is not new. NDEs have been investigated since the 1970s, beginning with the work of psychiatrist Raymond Moody, and decades ago psychiatrist Ian Stevenson documented alleged memories of past lives that would support reincarnation. We are now experiencing a boom, likely tied to a broader resurgence of spirituality, which has multiplied books on these topics and makes their authors go viral whenever they appear on a podcast. Not all of them are outsiders: among their supporters are leading researchers such as cardiologist Valentín Fuster, winner of the Prince of Asturias Award for Scientific and Technical Research, who wrote the foreword to Ego y supraconciencia (Ego and Supraconsciousness, Planeta, 2025) by surgeon Manuel Sans Segarra, who has had a prominent career at Bellvitge University Hospital. Robert W. Wilson, a Nobel laureate in physics for discovering the background radiation that confirmed the Big Bang, wrote the foreword to Bolloré and Bonnassies’s book.

One of the forerunners of this recent surge was Proof of Heaven (2012) by American neurosurgeon Eben Alexander, who spent 15 years on the faculty at Harvard Medical School. In November 2008 a bacterial meningitis left him in a coma for a week; upon waking he recounted what he interprets as a real journey to the afterlife. His testimony contains the elements many patients describe: an out-of-body experience — leaving the body and rising — encounters with beings of light or deceased relatives, and an instantaneous but thorough review of one’s life, all wrapped in a lucidity, peace, and love of unparalleled intensity.

For Alexander, this experience cannot be an hallucination like those induced by certain psychoactive substances: he argues that an experience of that intensity could hardly be produced while key brain areas were inoperative, as his were during the coma. He adds that, in his view, there are clear differences between an NDE — structured, persistent in memory and with lasting effects — and a hallucination, chaotic and fragmentary, that leaves little trace. “Life after death has been proven beyond any doubt from a scientific perspective. What happens is that some people are not interested enough to inform themselves,” the scientist says by videoconference.

However, other studies have questioned interpreting this phenomenon as proof of a transcendent reality. One is the study led by neuroscientist Charlotte Martial of the University of Liège, published last year in Nature Reviews Neurology. There, the authors propose a model that integrates decades of research and explains NDEs as the result of a cascade of neurobiological processes in a brain under extreme stress. Factors such as lack of oxygen, increased carbon dioxide, and alterations in electrical brain activity trigger neuronal hyperactivity and a massive release of neurotransmitters capable of producing intense, coherent, and emotionally deep experiences.

Beyond this experiment, one problem in studying NDEs and other transcendental phenomena is that they occur in an immaterial dimension, outside space and time. That places them beyond the reach of scientific tools. The scientific method is based on phenomena that can be observed, measured and reproduced. “We could demonstrate that those people saw something, not that that something was really there,” philosopher Carlos Blanco explains by phone; he is the author of Conciencia y mismidad (Consciousness and Selfhood, Dykinson, 2013). That something cannot be observed, he clarifies, does not imply it does not exist: “There is an order of being and an order of knowing — they are not the same.”

Part of science infers unobservable causes from indirect measurements. That is the case, for example, with electrons, which we do not see directly but through their effects, or with black holes, whose existence is inferred by how they affect surrounding matter and light. But there is a fundamental difference, explains philosopher of science Óscar Teixidó: electrons or black holes are not observed directly, yet they leave measurable, consistent traces in matter. By contrast, a consciousness outside space-time leaves no trace at all. “Not only is it unobservable, but it is also in another plane of existence,” he says.

Blanco says some of the supposed scientific proofs of God’s existence are a return to old philosophical arguments. The reasoning starts from an observable effect — that the universe has laws, order and constants so finely tuned they appear prepared to support life — and works backward from it to a cause, God, as Thomas Aquinas did. But from the effect, Blanco argues, one cannot deduce the cause: this falls into what logic calls the fallacy of affirming the consequent.

The same effect admits different explanations, and nothing in mere observation allows one to decide which is true. “Everything could be the result of chance, or that the universe is simply that way, eternal, or that other universes exist — multiverses. God is a possible cause, of course, but there are others. How do you decide which is correct if there are no observations or experiments?” he asks.

Another major criticism is about experimental rigor and the need to apply sufficiently demanding methodological standards. According to Teixidó, in recent years there has been an “intellectual backsliding” that has led to neglecting well-established principles: avoiding bias, distrusting anecdotal evidence and not being swayed by prior beliefs. “The problem is that exhaustive filters of rigor are not being applied. When you are demanding, many of these investigations boil down to three things: innocent confusions, deliberate errors, or simple myths. It’s smoke,” he says.

On the other side, Álex Gómez-Marín, senior researcher at the Institute of Neurosciences and principal scientist at the Spanish National Research Council (CSIC), who recounts the NDE he experienced in his book La ciencia del último umbral (The Science of the Final Threshold, Temas de Hoy, 2025), maintains that those who question the lack of experimental rigor are, in fact, uninformed. “These sorts of experts always say, in the name of science, that they know it’s not true, when in reality they do not know. And that has put many obstacles in the way of research and made many people who experience these phenomena feel foolish, crazy and alone. That is unscientific and unethical,” he says.

Given this dispute, it is worth recalling the foreword Albert Einstein wrote in 1930 for Mental Radio, a book by writer Upton Sinclair devoted to telepathy. The father of relativity did not accept Sinclair’s experiments as proven; on the contrary, he considered them beyond what a natural scientist might deem conceivable. But he did not dismiss them either: he regarded Sinclair as a scrupulous observer whose “good faith and reliability cannot be doubted,” and he reasoned that if those results were not due to telepathy but to some unconscious influence of one mind on another, the phenomenon would still be of great psychological interest. Neither credulity nor rejection: curiosity and rigor.

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