Lilian Weng shared today that she is leaving Thinking Machines Lab to focus on her health. I went back to this 2019 talk at OpenAI. In front of 100+ women in tech, she made a difficult frontier problem, teaching a robotic hand dexterous manipulation through reinforcement learning and domain randomization, feel understandable and worth exploring. That has always been part of Lilian’s impact. She didn’t just help build important systems. Through talks like this and Lil’Log, she opened up frontier research to an entire generation of researchers and builders. Wishing her the time and space to recover. As Lilian wrote today: “The future worth building is human.”