“You don’t know what you don’t know, but, when you know, you know” is one of my favorite sayings I use working in data science. It sounded to me it was something that Heraclitus would say.

Heraclitus was a pre-Socratic Greek philosopher known for his cryptic and paradoxical statements which emphasized change and the unity of opposites. His writings didn’t survive in full; fragments of his work have been preserved, and scholars have interpreted these to understand his philosophy. Here are some of his well-known quotes:

“No man ever steps in the same river twice, for it’s not the same river and he’s not the same man.”

“The only thing that is constant is change.”

“Character is destiny.”

“The path up and down is one and the same.”

“You could not discover the limits of the soul, even if you traveled every road. Such is the depth of its meaning.”

“The content of your character is your choice. Day by day, what you choose, what you think, and what you do is who you become.”

“Wisdom is the oneness of mind that guides and permeates all things.”

“Nature loves to hide.”

“There is nothing permanent except change.”

“Much learning does not teach understanding.”

“Listening not to me but to the Logos, it is wise to agree that all things are one.”

“The sun is new each day.”

“Everything flows, and nothing abides.”

“War is the father of all and the king of all; and some he has made gods and some men, some bond and some free.”

“Hidden wisdom and invisible treasure, there is no way to understand.”

“Immortal mortals, mortal immortals, live their death and die their life.”

“We step and do not step into the same rivers; we are and are not.”

“Even the barley drink decays if it remains unmoved.”

“Time is a game played beautifully by children.”

“Those who are awake all live in the same world. Those who are asleep live in their own worlds.”

“Dogs bark at what they don’t understand.”

“Because it is so unbelievable, the Truth often escapes being known.”

“If you do not expect the unexpected, you will not recognize it when it arrives.”

“Abundance of knowledge does not teach men to be wise.”

“Nothing is, everything is becoming.”

“Those who approach life like a child playing a game, moving and pushing pieces, possess the power of kings.”

“The world is nothing but a great desire to live and a great dissatisfaction with living.”

“To get everything you want is not a good thing. Disease makes health seem sweet. Hunger leads to the appreciation of being full-fed. Tiredness creates the enjoyment of resting.”

“The soul is dyed the color of its thoughts.”

“Big results require big ambitions.”

“Good character is not formed in a week or a month. It is created little by little, day by day.”