Professor Stephen Hawking, the theoretical physicist who died Wednesday at the age of 76, enthralled the world with his work and teachings on space, time, and the universe.

He had a knack for making his pioneering research accessible to the wider public, and his brilliance deepened our understanding of the universe and our place within it.

Throughout his illustrious career, he was known for his quick wit and humor, often demonstrated at conferences and in interviews with the press. He also offered insights on a whole range of subjects. Here are some of his most famous quotes:

On life

“Remember to look up at the stars and not down at your feet.” Hawking gave this now-famous piece of advice to his three children Lucy, Robert and Tim and related it in an interview with ABC’s Diane Sawyer in 2010. Included in those words of advice were: “Work gives you meaning and purpose and life is empty without it.” And: “if you are lucky enough to find love, remember it is there and don’t throw it away.”

Stephen Hawking to Diane Sawyer in 2010 on the most important advice he's given to his children (H/t @chrisdonovan)— Johnny Verhovek (@JTHVerhovek) March 14, 2018

“However bad life may seem, there is always something you can do, and succeed at. While there’s life, there is hope,” he told Hong Kong University of Science and Technology in 2006.

On living with a disability

“My advice to other disabled people would be, concentrate on things your disability doesn’t prevent you doing well, and don’t regret the things it interferes with. Don’t be disabled in spirit, as well as physically,” he told the New York Times in 2011. Hawking was frequently frank about his battle with ALS, a degenerative neurological disease that often proves fatal. But he defied doctors expectations, living for over half a century after he was diagnosed in 1963, at the age of 21. The year before, he said in an introduction to the 2010 TV documentary series Into the Universe with Stephen Hawking: “Although I cannot move and I have to speak through a computer, in my mind I am free.

"Don't be disabled in spirit as well as physically."Farewell, #StephenHawking— Philosopher Dogfox (@ProfesorRod) March 14, 2018

On being diagnosed with ALS

“My expectations were reduced to zero when I was 21. Everything since then has been a bonus,” he told the New York Times in 2004, after being asked how he kept his spirits up. “Life would be tragic if it weren’t funny.”

“My expectations were reduced to zero when I was 21. Everything since then has been a bonus." RIP Stephen Hawking.— Ava Williams (@adventureava) March 14, 2018

On being a celebrity

“The downside of my celebrity is that I cannot go anywhere in the world without being recognized,” he told an Israeli journalist in 2006. “It is not enough for me to wear dark sunglasses and a wig. The wheelchair gives me away.”

On the potential of humans

“We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special,” Hawking told German paper Der Spiegel in 1988. He often spoke about space exploration and the extent of human potential.

On women

“They are a complete mystery,” he said in an interview with The New Scientist magazine in 2012, having confessed to having spent most of his 70th birthday thinking not about the wonders of the cosmos, but about women.

On religion

“There is a fundamental difference between religion, which is based on authority, [and] science, which is based on observation and reason,” Hawking told ABC’s Diane Sawyer in 2010. “Science will win, because it works.” But his work wasn’t all dry rationality. “Science is not only a disciple of reason but, also, one of romance and passion,” he told PARADE magazine in 2010.

On the reason the universe exits

“If we find the answer to that, it would be the ultimate triumph of human reason — for then we would know the mind of God,” he wrote in his 1988 bestseller ‘A Brief History of Time’.

On finding alien life

On climate change

On Death

“I have lived with the prospect of an early death for the last 49 years. I’m not afraid of death, but I’m in no hurry to die. I have so much I want to do first,” Hawking said in an interview with The Guardian in May 2011.