Elon Musk says money will be 'irrelevant' if his vision of a multiplanetary future comes true

Elon Musk says his descendants might have a "tiny fraction" of his wealth.

Jae C.

Hong/AP Elon Musk says "money becomes irrelevant" if he's right about what the future holds.

The Tesla and SpaceX CEO said AI and robots will be better than humans at everything.

The world's richest man said his fortune could be virtually gone within a few generations.

Elon Musk says money could be meaningless one day, and the vast majority of his wealth will likely be gone within a few generations.

The world's richest person predicted that advances in robotics and space travel will create a multiplanetary economy, at which point "money becomes irrelevant" and "conventional currency will not matter." Value will be measured in mass and power or energy, he continued.

"So that's my guess," he said, adding that it seemed a "pretty obvious" outcome to him.

The Tesla and SpaceX CEO shared his vision of a post-money future and his outlook on his personal fortune with his biographer, Walter Isaacson, on "The Builders" podcast.

The interview was taped in early August and released on Tuesday.

Musk recommended earlier this year that people stop saving for retirement in 10 or 20 years, as he expects AI and other technologies to supercharge productivity and usher in an age of abundance where people can have "whatever stuff they want." He made a similar argument to Isaacson, saying "there won't be anything that humans can do that the AI and the robots can't do better." People will likely turn to hobbies like growing their own fruits and vegetables, or making art, to find purpose in life , he said.

Musk's plans for his own money Musk, who briefly became a trillionaire after SpaceX went public in June, topped the Bloomberg Billionaire Index at Monday's close with an estimated $920 billion net worth.

He defended his personal wealth on the podcast, saying that it mostly reflects his ownership of SpaceX and Tesla, and he needs large stakes in both companies to retain voting power and remain in charge .

His fortune is "going to be taxed quite heavily ," Musk said, adding that there isn't "some magical way to avoid taxes" because "if there were, I would know about it." Musk said his wealth will "get whittled down and a few generations from now — if money still matters, which I don't think it will — my descendants would have a tiny fraction of what I have." He also outlined what he hopes his foundation will spend his fortune on after he's gone: "Continue the goals .