Machine Heart

Jun 21, 2026 · Artificial Intelligence

Why the Once‑Rejected PPO Algorithm Became a Pillar of Modern LLM Training

The article recounts how Proximal Policy Optimization, initially dismissed by NeurIPS 2017 for limited novelty, later became a cornerstone of RLHF and large‑language‑model training, illustrating how academic evaluation can miss long‑term impact, with parallels to other once‑rejected breakthroughs such as LSTM, SIFT and Dropout.