“The only true wisdom is in knowing you know nothing.”

“We can know only that we know nothing. And that is the highest degree of human wisdom.”

“The only thing that we know is that we know nothing, and that is the highest flight of human wisdom.”

“Nothing has been discovered, nothing has been invented. We can only know that we know nothing. And that's the highest degree of human wisdom.”

“True knowledge exists in knowing that you know nothing.”

“If men learn this, it will implant forgetfulness in their souls; they will cease to exercise memory because they rely on that which is written, calling things to remembrance no longer from within themselves, but by means of external marks. What you have discovered is a recipe not for memory, but for reminder. And it is no true wisdom that you offer your disciples, but only its semblance, for by telling them of many things without teaching them you will make them seem to know much, while for the most part they know nothing, and as men filled, not with wisdom, but with the conceit of wisdom, they will be a burden to their fellows.”