When researchers at Hebrew University of Jerusalem followed the 2,000-year-old dissection instructions of Galen of Pergamum—the influential Roman physician—they hit a wall that no amount of detail could breach. The ancient text told them to cut "superficially" around the umbilicus until the underlying tissue appeared "whiter" than surrounding structures, but when they put scalpel to pig specimen, the instructions fell short. How much pressure is superficial? How should the hand move when resistance changes? What does tissue feel like when something goes wrong?
These questions matter because they expose a critical blind spot in modern medical education: the growing reliance on virtual reality, 3D models and digital simulations cannot capture the most essential ingredient in surgical training—tacit learning, the physical intuition that separates a competent physician from one who truly understands their craft.
Prof. Orly Lewis and her multidisciplinary team published their findings in Nature Medicine, arguing that as medical schools increasingly embrace digital tools, they risk losing something that has never been transmitted through words or images alone. While augmented reality and virtual reality can teach anatomy, procedures and decision-making with remarkable sophistication, they struggle to transmit what clinicians call "tacit knowledge"—the feel of how much pressure to apply, where to place one's hands, when tissue feels wrong, when to stop.
"We can program the visible steps of a procedure, but simulations still struggle to transmit the physical intuition of an experienced physician," Lewis, principal investigator of the ATLOMY project at Hebrew University, explained in the correspondence. Galen's text was extraordinarily detailed for its era, yet even those meticulous ancient instructions left something essential unsaid.
The stakes for medical education are rising. As opportunities for physical dissection, bedside teaching and supervised clinical practice decline in some settings, institutions are turning to digital resources at an accelerating pace. Contemporary competency-based training breaks complex procedures into discrete steps that can be taught, measured and assessed—but this fragmentation may obscure the unspoken elements of expertise that have traditionally passed from teacher to student through observation, imitation, correction and repeated hands-on practice.
Whether a trainee is placing a catheter, making an incision, palpating tissue or navigating the unique anatomy of an individual patient, clinical competence depends on more than knowing what to do. It requires developing the sensory judgment to do it safely and effectively—something that exists in the realm of embodied knowledge, not digital specification.
The researchers are not calling for a retreat from innovation. Instead, they argue for a more rigorous approach to designing digital tools. If virtual reality and augmented reality are to replace or supplement hands-on training, they must identify and incorporate the tacit dimensions of medical skill acquisition: touch, pressure, resistance, timing and embodied judgment. The challenge is immense, but so is the necessity. Future surgeons deserve training that honors both the precision of science and the irreplaceable wisdom of hands that have learned through doing.
The lesson from Galen resonates across twenty centuries: Medical knowledge has never been fully captured in instruction alone. That missing knowledge may be exactly what the next generation of physicians needs most.