"The nuclear genie has proliferated considerably since it was first released," he said in a 1996 lecture.
But in retrospect, this decision appears to have been less than responsible, especially in letting the nuclear genie out of the bottle forever.
He added: "There are countries and people that want to put the nuclear genie back in the bottle.
There is no formal agenda, but whatever the drift of the conversation, the nuclear genie will undoubtedly hover above the proceedings.
Einstein hadn't lived to see it, but his impossible dream of putting his nuclear genie back in the bottle had come to pass.
As both Albert Einstein and J. Robert Oppenheimer predicted, the nuclear genie, once uncorked, will never return to its bottle.
If the nuclear genie pops out of the bottle, I don't know what the world will look like afterward.
The nuclear genie has escaped its bottle.
It's unfortunate that the Pugwash meetings started only well after the nuclear genie was out of the bottle - roughly 15 years too late.
Our nuclear genie is out of the bottle.