Open weights
An open-weight model is one whose trained weights (the numbers that make up the model) are published for anyone to download, run and modify. It differs from fully open-source AI, which by the Open Source Initiative's 2024 definition also requires the code and detailed information about the training data. Once released, weights cannot be recalled, and any safety training can be removed.
Why it comes up
LeCun and Ng defend open-weight models as necessary for competition, research and security, while Hinton opposes releasing the weights of the largest models and Bengio argues the decision should not rest with companies alone.
People and milestones
The LLaMA leak, 2023
Llama 2, 2023
DeepSeek-R1, 2025
GPT-2 and its staged release, 2019
Yann LeCun
Andrew Ng
Geoffrey Hinton
Yoshua Bengio
Yann LeCun
Andrew Ng
Geoffrey Hinton
Yoshua Bengio