Despite being the most universal human experience, aging remains a scientific enigma. A recent survey conducted at the Gordon Research Conference in Newry, Maine, has revealed just how little consensus exists among experts in the field. Over a week of presentations and discussions, 103 attendees responded to nine core questions, including what constitutes aging, when it begins, and what might qualify as rejuvenation. The results, summarized in a study published in PNAS Nexus and covered in Nature, show that no single answer received more than 50 percent agreement. Even the necessity of defining aging itself divided opinion among respondents.
“The most prevalent human mortality risk factor—aging—seems to still be hidden in the mist,” the study concludes. With 82 co-authors contributing, the paper underscores that no treatment has been definitively proven to slow aging in humans. As the authors note, even when discussing aging, scientists often assume they are speaking about the same process, when in fact their perspectives differ considerably. Manuel Collado, leader of the Cell Senescence, Cancer, and Aging Laboratory at the Spanish National Research Center (CNB-CSIC) and the University of Santiago de Compostela, cautions that variations in definitions are natural but believes there is an underlying consensus on aging’s general features. Mariona Jové, professor at the University of Lleida and scientist at the Lleida Biomedical Research Institute, expressed surprise at the findings, noting that researchers “pretty much explain it in a similar way,” yet acknowledges the complexity that the survey revealed.
The study highlights the diversity of definitions. Collado describes aging as “a loss of functionality of the cells and tissues with the passage of time,” while Jové defines it as “a set of harmful changes that affect cells, organs, and systems, leading to loss of function and increased risk of disease.” Both emphasize function, yet these were only the most popular responses, accounting for 30 percent of participants. Others focused on damage accumulation, general biological changes, health status, or increased mortality risk. A few described aging as simply a “deviation from the ideal state,” demonstrating the difficulty of capturing such a multifaceted process in a single definition.
Causes of aging were similarly contested. Some researchers cited the accumulation of molecular and cellular damage, while others pointed to evolutionary pressures or broader physiological imbalances. Several respondents admitted they simply did not know. The survey’s authors argue that this lack of consensus leads to divergent research strategies, fragmented funding, and inconsistent objectives, slowing the field’s overall progress. A 2020 Canadian study, led by biologist Alan Cohen, went even further, suggesting that aging may not exist as a single biological phenomenon but rather as a collection of disparate processes. The study argues that the very language we use to describe aging may generate confusion and mislead research efforts, particularly as the field moves toward potential anti-aging interventions.
Despite these philosophical disagreements, experts acknowledge practical markers for studying aging. Molecular clocks, epigenetic changes, and other biomarkers offer approximate ways to measure biological age, though no method has proven capable of halting or reversing aging in humans. Interventions that extend lifespan in laboratory animals—including pharmaceuticals like metformin and rapamycin, senolytics that remove senescent cells, and calorie restriction—remain experimental in humans. Collado notes that while calorie restriction is the most widely recognized approach, promising research continues on other mechanisms. Landmark studies, including work co-authored by Spanish researchers Carlos López-Otín, María Blasco, and Manuel Serrano, have identified up to twelve canonical mechanisms of aging.
Survey responses also highlighted uncertainty about when aging begins. Among nine options, the most common response, chosen by just 22 percent of participants, was age 20. Others suggested it starts during conception or even in the early weeks of development. While gerontologists generally accept that observable aging processes emerge in early adulthood, the precise starting point remains scientifically debated. Similarly, the question of whether aging constitutes a disease drew nearly equal affirmative and negative responses, illustrating further conceptual ambiguity.
The survey emphasizes that while definitions and debates matter for research, practical approaches to aging remain grounded in promoting healthy life. Juan Manuel Pérez Castejón, vice-president of the Spanish Society of Geriatrics and Gerontology (SEGG), stresses that geriatricians focus on aging well rather than stopping it. Jové concurs, framing the goal as “dying of old age, not of illness.” Collado adds that while philosophical clarity is valuable, language is inherently imperfect, and what matters is generating new knowledge to guide interventions effectively.
The survey also highlights broader societal questions. In an era where some billionaires seek eternal life, the general population prioritizes simply living to see the next day. As writer Santiago Alba Rico observed, “The rich and powerful want to live forever; the poor want to live to see another day.” This contrast underscores the gap between scientific ambition and public expectation, and the challenge of translating complex research into meaningful strategies for population health.
