Dario Amodei, the chief executive of the artificial intelligence company Anthropic, published a 3,800-word open letter on Saturday calling for a slowdown in the development of A.I.

The essay prompted other A.I. leaders, including Sam Altman, the chief executive of OpenAI; Elon Musk, SpaceX’s chief executive; and Demis Hassabis, the chair of Google DeepMind, to speak out in agreement.

Here are the key arguments that Dr. Amodei made in his essay:

Why A.I. Needs to Slow Down

Dr. Amodei said two recent developments convinced him that simply investing in A.I. safety was no longer enough.

One, he said, was that A.I. itself had begun helping to build the next generation of A.I., a self-reinforcing loop called “recursive self-improvement” that could soon outrun humans’ ability to understand or control what they were creating.