Bill Gates is concerned about growing U.S. isolationism

Bill Gates is known for being one of the world's biggest optimists, in addition to one of its largest philanthropists. But Gates is concerned about the impact if the U.S. follows through on plans to cut foreign aid.

"Overall like Warren Buffett I am optimistic about the long run," Gates said during a Reddit AMA (Ask Me Anything) forum. "I am concerned in the short run that the huge benefits of how the US works with other countries may get lost. This includes the aid we give to Africa to help countries there get out of the poverty trap."

Gates, who has said the idea of a "robot tax" is worth exploring to slow the pace at which human jobs are automated, says the notion of a guaranteed basic income probably isn't an option — at least for now.

"Over time countries will be rich enough to do this. However we still have a lot of work that should be done — helping older people, helping kids with special needs, having more adults helping in education. Even the U.S. isn't rich enough to allow people not to work. Some day we will be but until then things like the Earned Income Tax Credit will help increase the demand for labor."

Gates expressed other concerns, including his usual priorities around clean energy, improving education, eradicating disease and making sure artificial intelligence doesn't wipe out humanity. And he weighed in on the decades-old question of whether Microsoft copied Apple in creating Windows.

The Microsoft co-founder also took some time to address lighthearted issues, including offering up his top vacation picks (Australia and the Amazon) and how he sometimes wears a hat to disguise himself in public.