Knowing something and understanding it were not the same thing.

'Yes, Professor, knowledge and understanding are quite different. Only understanding can lead to being, whereas knowledge is but a passing presence in it. New knowledge displaces the old and the result is, as it were, a pouring from the empty into the void.

We imagined we knew everything the other thought, even when we did not necessarily want to know it, but in fact, I have come to see, we knew not the smallest fraction of what there was to know.

I do not need to know all things. I remind myself that it is sufficient that I know what I know and know that without believing that I will always know what I know or that what I know will always be true.

People who do not understand themselves have a craving for understanding — a thing which is rather surmised and never spoken than known and clothed in words.

La errónea idea que tenía de las cosas me inducía a creer que, para leer un libro con provecho, era necesario poseer todos los conocimientos que el mismo suponía, bien lejos de sospechar que con frecuencia carecía de ellos el mismo autor, quien iba a buscarlos en otros libros a medida que los necesitaba.

There is something I don't know
that I'm supposed to know.
I don't know what it is I don't know,
and yet I'm supposed to know,
and I feel stupid
if I seem both to not know it
and not know what it is I don't know.
Therefore I pretend to know it.
This is nerve-racking
since I don't know what I must pretend to know.
Therefore I pretend to know everything.

Understanding means throwing away your knowledge.

There was also something panicked about my desire to acquire knowledge, in sudden terrible insights I saw that actually I didn’t know anything and it was urgent, I didn’t have a second to lose. It was almost impossible to adapt this urgency to the slowness that reading required.

I know too much and not enough

...The more I learned the more I realized how very much one has to know before one is in-the-know at all.

The vast accumulations of knowledge — or at least of information — deposited by the nineteenth century have been responsible for an equally vast ignorance. When there is so much to be known, when there are so many fields of knowledge in which the same words are used with different meanings, when every one knows a little about a great many things, it becomes increasingly difficult for anyone to know whether he knows what he is talking about or not. And when we do not know, or when we do not know enough, we tend always to substitute emotions for thoughts.

A lot of people have thought of understanding as just knowledge of true causes, but then there is a problem of why we value knowledge - if not to understand things. And in effect understanding is what underwrites the desire for knowledge in the context of science.

To have real knowledge, one must understand the essence of things and not only their manifestations.