“Simplicity of structure means organic unity, whether the organism be simple or complex; and hence in all times the emphasis which critics have laid upon Simplicity, though they have not unfrequently confounded it with narrowness of range.”

“If we study the history of science we see happen two inverse phenomena… Sometimes simplicity hides under complex appearances; sometimes it is the simplicity which is apparent, and which disguises extremely complicated realities.
…No doubt, if our means of investigation should become more and more penetrating, we should discover the simple under the complex, then the complex under the simple, then again the simple under the complex, and so on, without our being able to foresee what will be the last term. We must stop somewhere, and that science may be possible, we must stop when we have found simplicity. This is the only ground on which we can rear the edifice of our generalizations.”

Henri Poincaré book Science and Hypothesis

“Most of the world is of great roughness and infinite complexity. However, the infinite sea of complexity includes two islands of simplicity: one of Euclidean simplicity and a second of relative simplicity in which roughness is present but is the same at all scales.”

Benoît Mandelbrot (1924–2010) Polish-born, French and American mathematician

“The ideas need not be complex. Most ideas that are successful are ludicrously simple. Successful ideas generally have the appearance of simplicity because they seem inevitable.”

Sol LeWitt (1928–2007) American artist

“Pure, holy simplicity confounds all the wisdom of this world and the wisdom of the flesh.”

Francis of Assisi (1182–1226) Catholic saint and founder of the Franciscan Order

“A leader's intelligence must have simplicity and clarity; action is difficult when the mind is full of complex theories and schemes. An over-organized industry wastes just as much money as one without organization - the transmission uses up all the motor's power. (For this reason small enterprises directed by one man have the better of larger trusts because their costs are less and the quality of their product higher.) A leader must have a few very simple ideas, acquired from experience and confirmed by putting them into practice. This structure created by experience will contain much exact knowledge for use in connection with a given action.”

André Maurois (1885–1967) French writer

“… the only simplicity to be trusted is the simplicity to be found on the far side of complexity.”

Alfred North Whitehead (1861–1947) English mathematician and philosopher

“Simplicity is not a simple thing.”

Charlie Chaplin (1889–1977) British comic actor and filmmaker

“There is a very stunning range of studies… of interstellar organic matter… the cold, dark spaces between the stars are also loaded with organic matter. …complex organic materials are everywhere.”

Carl Sagan (1934–1996) American astrophysicist, cosmologist, author and science educator

“Simplicity is not so simple to attain.”

Nassim Nicholas Taleb book Antifragile: Things That Gain from Disorder