moving:
Mao Pigeon
"Whoever wants to know a thing has no way of doing so except by coming into contact with it, that is, by living (practicing) in its environment. ... If you want knowledge, you must take part in the practice of changing reality. If you want to know the taste of a pear, you must change the pear by eating it yourself.... If you want to know the theory and methods of revolution, you must take part in revolution. All genuine knowledge originates in direct experience."
sources:
Mao Zedong "On Practice," (July 1937), Selected Works, Vol. I, pp. 299-300. via marxists.org
photo: "Mao Zedong's Proclamation of The People's Republic of China during a Speech on October 1, 1949" digitized by Orihara1 at wikimedia. English description: "Obtained the original monochromatic photograph of Mao Zedong, chairman of the Chinese Communist Party, proclaiming the People's Republic of China on 1 October, 1949." PD-public domain by date.