Bill Gates is often called Harvard’s most famous dropout. He notably ditched the top university in 1975 to found Microsoft, and became the world’s richest man.
Looking back, Gates has said he was lucky that computers were a hobby and an obsession of his at a time when they were just starting to change the world.
But speaking on Friday at another Ivy League university, Columbia University, along with fellow billionaire and famous investor Warren Buffett, Gates said that if he were to drop out of college today there’s a limited chance he would end up in the computer industry, and likely not in developing operating software for companies. Roughly 1,000 people, mostly students, gathered on the campus to hear the two billionaires speak.
To be clear, Gates, who’s now 61, wasn’t at Columbia to advocate that students drop out of school. Gates believes in investing in education, and he said that is the No. 1 priority of his foundation in the United States. Nonetheless, responding to a question from a student, he named three areas that he said he found very promising, and where he might pursue a career if he were starting out today. Here they are:
If he were to go into computer sciences today, Gates said, the area that he thought had the most potential was artificial intelligence. Gates brought up a recent victory by Google DeepMind over the top player in the world at Go, a game some predicted a computer could never master. He called it a remarkable achievement that signaled there is more to come in advancement in artificial intelligence. And he said the research being done in the field now is “profound” and on the verge of making new breakthroughs. “The ability for artificial agents to read and understand material is going to be phenomenal,” says Gates. “Anything connected with that would be an exciting lifetime career.”
Gates said there is a huge and growing demand for energy that’s “reliable, cheap, and clean.” And Gates said there is no system yet today that can provide enough energy that meets those criteria. That’s why he sees energy as an area of opportunity for innovative minds, he told the audience of mostly university students. “The innovations [in energy] will be profound,” said Gates. “And there are many paths to get to where we need to go”
Buffett, oddly, didn’t chime in, but he would probably agree. His conglomerate Berkshire Hathaway owns a number of the nation’s largest utilities and has pledged to spend $30 billion developing alternative energy. Berkshire owns a number of wind farms, and will soon become the largest producer of wind energy in America.
Gates said he thinks it is a thrilling time in biology and that developments in the biosciences are “moving faster than ever.” He said he thought there was potential, and a need for smart innovation, in the fights against obesity, cancer, and depression. Among the most promising advances that Gates mentioned was DNA vaccines. On Donald Trump, Gates said that he was optimistic that the U.S.’s policy and spending on vaccines wouldn’t change under the new president, despite some comments Trump has made raising concerns about scientifically unproven links between vaccines and autism. “I don’t think Trump will change the U.S. policy stance on vaccines,” Gates said. “There may be a commission but the evidence [for the use of vaccines] is unequivocal.”
This story originally appeared on Fortune.