No one really knew why tokamaks were able to achieve such impressive results. The Soviets didn’t progress by building out detailed theory, but by simply following what seemed to work without understanding why. Rather than a detailed model of the underlying behavior of the plasma, progress on fusion began to take place by the application of “scaling laws,” empirical relationships between the size and shape of a tokamak and various measures of performance. Larger tokamaks performed better: the larger the tokamak, the larger the cloud of plasma, and the longer it would take a particle within that cloud to diffuse outside of containment. Double the radius of the tokamak, and confinement time might increase by a factor of four. With so many tokamaks of different configurations under construction, the contours of these scaling laws could be explored in depth: how they varied with shape, or magnetic field strength, or any other number of variables.

Hadn't come across this analogy to current LLMs. Source: This interesting article.