Fine-Tuning Isn’t Just Supervised: Why SFT Is Really RL in Disguise
TL;DR for operators Fine-tuning on curated examples is usually sold as the boring, stable cousin of reinforcement learning. The paper behind this article says that is too neat. When a team filters examples into “good” and “not good,” it has already created a sparse reward function. Standard supervised fine-tuning on the surviving examples is therefore not outside reinforcement learning; it is optimising a lower bound on an RL objective, only without admitting it at the meeting. ...