Stephen Hawking has said he would consider assisted suicide, especially if he felt as though he’d become a “burden” to his loved ones.

“To keep someone alive against their wishes is the ultimate indignity,” the 73-year-old physicist told comedian Dara O’Briain in an interview that will air on the BBC, according to The Guardian.

He added: “I would consider assisted suicide only if I were in great pain or felt I had nothing more to contribute but was just a burden to those around me.”

Hawking was diagnosed with a motor neuron disease when he was 21 and has used a wheelchair for decades. Still, he believes he has more to add to the world.

“I am damned if I’m going to die before I have unravelled more of the universe,” he said.

This article originally appeared on People.com

Get our Space Newsletter. Sign up to receive the week's news in space. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Contact us at letters@time.com.