In 2007, Kirk Douglas told Esquire's Mike Sager "The learning process continues until the day you die." Following his death on Wednesday, his son, actor Michael Douglas, released a statement detailing some of the things he learned from his late father, whose career spanned eight decades in Hollywood as an actor, producer, director, and writer.

Michael's post on Instagram said:

It is with tremendous sadness that my brothers and I announce that Kirk Douglas left us today at the age of 103. To the world he was a legend, an actor from the golden age of movies who lived well into his golden years, a humanitarian whose commitment to justice and the causes he believed in set a standard for all of us to aspire to.

But to me and my brothers Joel and Peter he was simply Dad, to Catherine, a wonderful father-in-law, to his grandchildren and great grandchild their loving grandfather, and to his wife Anne, a wonderful husband.

Kirk's life was well lived, and he leaves a legacy in film that will endure for generations to come, and a history as a renowned philanthropist who worked to aid the public and bring peace to the planet.

Let me end with the words I told him on his last birthday and which will always remain true. Dad- I love you so much and I am so proud to be your son. #KirkDouglas

At the peak of his career, Douglas was "as big a star as there was — a member of a pantheon of leading men, among them Burt Lancaster, Gregory Peck, Steve McQueen and Paul Newman, who rose to fame in the postwar years," said The New York Times' Robert Berkvist. Douglas died Wednesday in his home in Beverly Hills. He was 103.