To achieve accurate knowledge ...

To achieve accurate knowledge of others, if such a thing were possible, we could only ever arrive at it through the slow and unsure recognition of our own initial optical inaccuracies. However, such knowledge is not possible: for, while our vision of others is being adjusted, they, who are not made of mere brute matter, are also changing; we think we have managed to see them more clearly, but they shift; and when we believe we have them fully in focus, it is merely our older images of them that we have clarified, but which are themselves already out of date.
To achieve accurate knowledge of others, if such a thing were possible, we could only ever arrive at it through the slow and unsure recognition of our own initial optical inaccuracies. However, such knowledge is not possible: for, while our vision of others is being adjusted, they, who are not made of mere brute matter, are also changing; we think we have managed to see them more clearly, but they shift; and when we believe we have them fully in focus, it is merely our older images of them that we have clarified, but which are themselves already out of date.

Quotes from the same author

We don't receive wisdom; we must discover it for ourselves after a journey that no one can take for us or spare us.
Let us be grateful to people who make us happy; they are the charming gardeners who make our souls blossom.
The truth is that men can have several sorts of pleasure. The true pleasure is the one for which they abandon the other.
For everyone who, having no artistic sense-that is to say, no submission to subjective reality-may have the knack of reasoning about art till doomsday, especially if he be, in addition, a diplomat or financier in contact with the 'realities' of the present day, is only too ready to believe literature is an intellectual game which is destined to gradually be abandoned as time goes on.
We are able to find everything in our memory, which is like a dispensary or chemical laboratory in which chance steers our hand sometimes to a soothing drug and sometimes to a dangerous poison.